diff --git a/src/anonymous_range.h b/src/anonymous_range.h
index 5b87367..cbf6e82 100644
--- a/src/anonymous_range.h
+++ b/src/anonymous_range.h
@@ -44,7 +44,7 @@ namespace MultiArrayTools
 	
 	virtual IndexType begin() const override;
 	virtual IndexType end() const override;
-	virtual std::shared_ptr<IndexBase> index() const override;
+	virtual std::shared_ptr<VIWB> index() const override;
 	
 	friend AnonymousRangeFactory;
 	
@@ -155,11 +155,12 @@ namespace MultiArrayTools
     }
 
     // put this in the interface class !!!
-    std::shared_ptr<IndexBase> AnonymousRange::index() const
+    std::shared_ptr<VIWB> AnonymousRange::index() const
     {
-	return std::make_shared<SingleIndex >
-	    ( std::dynamic_pointer_cast<AnonymousRange>
-	      ( std::shared_ptr<RangeBase>( RB::mThis ) ) );
+	return std::make_shared<VIWB>
+	    (std::make_shared<SingleIndex >
+	     ( std::dynamic_pointer_cast<AnonymousRange>
+	       ( std::shared_ptr<RangeBase>( RB::mThis ) ) ) );
     }
 }
 
diff --git a/src/base_def.h b/src/base_def.h
index ca81680..c84f2d5 100644
--- a/src/base_def.h
+++ b/src/base_def.h
@@ -64,10 +64,15 @@ namespace MultiArrayTools
     class RangeInterface;
 
     // index_base.h
-    class IndexBase;
-
+    class VirtualIndexWrapperBase;
+    typedef VirtualIndexWrapperBase VIWB;    
+    
     // index_base.h
-    template <typename MetaType>
+    template <class I>
+    class IndexWrapper;
+    
+    // index_base.h
+    template <class I, typename MetaType>
     class IndexInterface;
 
     // single_range.h    
diff --git a/src/container_range.h b/src/container_range.h
index 902ce65..5efa01e 100644
--- a/src/container_range.h
+++ b/src/container_range.h
@@ -17,64 +17,144 @@ namespace MultiArrayTools
 {
     
     template <class... Indices>
-    class ContainerIndex : public IndexInterface<std::tuple<typename Indices::MetaType...> >
+    class ContainerIndex : public IndexInterface<ContainerIndex<Indices...>,
+						 std::tuple<typename Indices::MetaType...> >
     {
     public:
 
-	typedef IndexBase IB;
+	typedef IndexInterface<ContainerIndex<Indices...>,
+			       std::tuple<typename Indices::MetaType...> > IB;
 	typedef std::tuple<typename Indices::MetaType...>  MetaType;
 	typedef std::tuple<std::shared_ptr<Indices>...> IndexPack;
-	typedef IndexInterface<std::tuple<typename Indices::MetaType...> > IndexI;
 	typedef ContainerRange<typename Indices::RangeType...> RangeType;
 
-    protected:
+    private:
+
+	friend IB;
+	
 	bool mExternControl = false;
 	IndexPack mIPack;
 	std::array<size_t,sizeof...(Indices)+1> mBlockSizes; 
 	
     public:
 	ContainerIndex() = delete;
+	
+	template <class MRange>
+	ContainerIndex(const std::shared_ptr<MRange>& range);
+
+	template <size_t N>
+	auto get() const -> decltype( *std::get<N>( mIPack ) )&;
+
+	ContainerIndex& sync(); // recalculate 'IB::mPos' when externalControl == true
+	ContainerIndex& operator()(const std::shared_ptr<Indices>&... inds); // control via external indices
+	ContainerIndex& operator()(); // -> sync; just to shorten the code
+	
+    private:
 
 	//ContainerIndex(const ContainerIndex& in);
 	//ContainerIndex& operator=(const ContainerIndex& in);
 
-	template <class MRange>
-	ContainerIndex(const std::shared_ptr<MRange>& range);
-
-	virtual IndexType type() const override;
+	// ==== >>>>> STATIC POLYMORPHISM <<<<< ====
 	
-	virtual ContainerIndex& operator++() override;
-	virtual ContainerIndex& operator--() override;
-	virtual ContainerIndex& operator=(size_t pos) override;
-
-	virtual int pp(std::shared_ptr<IndexBase>& idxPtr) override;
-	virtual int mm(std::shared_ptr<IndexBase>& idxPtr) override;
+	static IndexType S_type(ContainerIndex* i) { return IndexType::CONT; }
 	
-	virtual MetaType meta() const override;
-	virtual ContainerIndex& at(const MetaType& metaPos) override;
-
-	virtual bool first() const override;
-	virtual bool last() const override;
+	static ContainerIndex& S_pp_op(ContainerIndex* i)
+	{
+	    if(i->mExternControl){
+		i->mPos = PackNum<sizeof...(Indices)-1>::makePos(i->mIPack);
+	    }
+	    PackNum<sizeof...(Indices)-1>::pp( i->mIPack );
+	    ++i->mPos;
+	    return *i;
+	}
 	
-	virtual size_t dim() const override;
+	static ContainerIndex& S_mm_op(ContainerIndex* i)
+	{
+	    if(i->mExternControl){
+		i->mPos = PackNum<sizeof...(Indices)-1>::makePos(i->mIPack);
+	    }
+	    PackNum<sizeof...(Indices)-1>::mm( i->mIPack );
+	    --i->mPos;
+	    return *i;
 
-	ContainerIndex& sync(); // recalculate 'IB::mPos' when externalControl == true
+	}
+
+	static ContainerIndex& S_ass_op(ContainerIndex* i, size_t pos)
+	{
+	    i->mPos = pos;
+	    PackNum<sizeof...(Indices)-1>::setIndexPack(i->mIPack, pos);
+	    return *i;
+	}
+
+	static int S_pp(ContainerIndex* i, intptr_t idxPtrNum)
+	{
+	    int tmp = PackNum<sizeof...(Indices)-1>::pp(i->mIPack, i->mBlockSizes, idxPtrNum);
+	    i->mPos += tmp;
+	    return tmp;
+	}
+
+	static int S_mm(ContainerIndex* i, intptr_t idxPtrNum)
+	{
+	    int tmp = PackNum<sizeof...(Indices)-1>::mm(i->mIPack, i->mBlockSizes, idxPtrNum);
+	    i->mPos -= tmp;
+	    return tmp;
+	}
+	
+	static MetaType S_meta(ContainerIndex* i)
+	{
+	    MetaType metaTuple;
+	    PackNum<sizeof...(Indices)-1>::getMetaPos(metaTuple, i->mIPack);
+	    return metaTuple;
+	}
+
+	static ContainerIndex& S_at(ContainerIndex* i, const MetaType& metaPos)
+	{
+	    PackNum<sizeof...(Indices)-1>::setMeta(i->mIPack, metaPos);
+	    i->mPos = PackNum<sizeof...(Indices)-1>::makePos(i->mIPack);
+	    return *i;
+	}
+
+	static size_t S_dim(ContainerIndex* i)
+	{
+	    return sizeof...(Indices);
+	}
+
+	static bool S_first(ContainerIndex* i)
+	{
+	    return i->pos() == 0;
+	}
+
+	static bool S_last(ContainerIndex* i)
+	{
+	    return i->pos() == i->mMax - 1;
+	}
 	
 	template <size_t N>
-	auto get() const -> decltype( *std::get<N>( mIPack ) )&;
+	static auto S_getPtr(ContainerIndex* i) -> decltype( std::get<N>( mIPack ) )&
+	{
+	    return std::get<N>( i->mIPack );
+	}
 	
-	template <size_t N>
-	auto getPtr() const -> decltype( std::get<N>( mIPack ) )&;
+	static std::shared_ptr<VIWB> S_getVPtr(ContainerIndex* i, size_t n)
+	{
+	    if(n >= sizeof...(Indices)){
+		assert(0);
+		// throw !!
+	    }
+	    ContainerIndex<Indices...> const* t = i;
+	    return PackNum<sizeof...(Indices)-1>::getIndexPtr(*t, n);
+	}
 
-	virtual std::shared_ptr<IndexBase> getPtr(size_t n) const override;
-	virtual size_t getStepSize(size_t n) const override;
+	static size_t S_getStepSize(ContainerIndex* i, size_t n)
+	{
+	    if(n >= sizeof...(Indices)){
+		assert(0);
+		// throw !!
+	    }
+	    return i->mBlockSizes[n+1];
+	}
 	
-	ContainerIndex& operator()(const std::shared_ptr<Indices>&... inds); // control via external indices
-
-	ContainerIndex& operator()(); // -> sync; just to shorten the code
-
-	std::shared_ptr<RangeType> range() const;
-	virtual std::string id() const override { return std::string("con") + std::to_string(IB::mId); }
+	static std::string S_id(ContainerIndex* i) { return std::string("con") + std::to_string(IB::mId); }
     };
 
     
@@ -131,7 +211,7 @@ namespace MultiArrayTools
 	virtual IndexType begin() const override;
 	virtual IndexType end() const override;
 	
-	virtual std::shared_ptr<IndexBase> index() const override;
+	virtual std::shared_ptr<VIWB> index() const override;
 
 	friend ContainerRangeFactory<Ranges...>;
 	
@@ -157,7 +237,7 @@ namespace MultiArrayTools
     template <class... Indices>
     template <class MRange>
     ContainerIndex<Indices...>::ContainerIndex(const std::shared_ptr<MRange>& range) :
-	IndexInterface<std::tuple<typename Indices::MetaType...> >(range, 0)
+	IndexInterface<ContainerIndex<Indices...>,std::tuple<typename Indices::MetaType...> >(range, 0)
     {
 	PackNum<sizeof...(Indices)-1>::construct(mIPack, *range);
 	IB::mPos = PackNum<sizeof...(Indices)-1>::makePos(mIPack);
@@ -165,81 +245,6 @@ namespace MultiArrayTools
 	PackNum<sizeof...(Indices)-1>::initBlockSizes(mBlockSizes, mIPack);
     }
 
-    template <class... Indices>
-    IndexType ContainerIndex<Indices...>::type() const
-    {
-	return IndexType::CONT;
-    }
-    
-    template <class... Indices>
-    ContainerIndex<Indices...>& ContainerIndex<Indices...>::operator++()
-    {
-	if(mExternControl){
-	    IB::mPos = PackNum<sizeof...(Indices)-1>::makePos(mIPack);
-	}
-	PackNum<sizeof...(Indices)-1>::pp( mIPack );
-	++IB::mPos;
-	return *this;
-    }
-
-    template <class... Indices>
-    ContainerIndex<Indices...>& ContainerIndex<Indices...>::operator--()
-    {
-	if(mExternControl){
-	    IB::mPos = PackNum<sizeof...(Indices)-1>::makePos(mIPack);
-	}
-	PackNum<sizeof...(Indices)-1>::mm( mIPack );
-	--IB::mPos;
-	return *this;
-
-    }
-
-    template <class... Indices>
-    ContainerIndex<Indices...>& ContainerIndex<Indices...>::operator=(size_t pos)
-    {
-	IB::mPos = pos;
-	PackNum<sizeof...(Indices)-1>::setIndexPack(mIPack, pos);
-	return *this;
-    }
-
-    template <class... Indices>
-    int ContainerIndex<Indices...>::pp(std::shared_ptr<IndexBase>& idxPtr)
-    {
-	int tmp = PackNum<sizeof...(Indices)-1>::pp(mIPack, mBlockSizes, idxPtr);
-	IB::mPos += tmp;
-	return tmp;
-    }
-
-    template <class... Indices>
-    int ContainerIndex<Indices...>::mm(std::shared_ptr<IndexBase>& idxPtr)
-    {
-	int tmp = PackNum<sizeof...(Indices)-1>::mm(mIPack, mBlockSizes, idxPtr);
-	IB::mPos -= tmp;
-	return tmp;
-    }
-    
-    template <class... Indices>
-    typename ContainerIndex<Indices...>::MetaType ContainerIndex<Indices...>::meta() const
-    {
-	MetaType metaTuple;
-	PackNum<sizeof...(Indices)-1>::getMetaPos(metaTuple, mIPack);
-	return metaTuple;
-    }
-
-    template <class... Indices>
-    ContainerIndex<Indices...>& ContainerIndex<Indices...>::at(const MetaType& metaPos)
-    {
-	PackNum<sizeof...(Indices)-1>::setMeta(mIPack, metaPos);
-	IB::mPos = PackNum<sizeof...(Indices)-1>::makePos(mIPack);
-	return *this;
-    }
-
-    template <class... Indices>
-    size_t ContainerIndex<Indices...>::dim() const
-    {
-	return sizeof...(Indices);
-    }
-
     template <class... Indices>
     ContainerIndex<Indices...>& ContainerIndex<Indices...>::sync()
     {
@@ -259,47 +264,6 @@ namespace MultiArrayTools
 	return *std::get<N>( mIPack );
     }
 
-    template <class... Indices>
-    template <size_t N>
-    auto ContainerIndex<Indices...>::getPtr() const -> decltype( std::get<N>( mIPack ) )&
-    {
-	return std::get<N>( mIPack );
-    }
-
-    template <class... Indices>
-    std::shared_ptr<IndexBase> ContainerIndex<Indices...>::getPtr(size_t n) const
-    {
-	if(n >= sizeof...(Indices)){
-	    assert(0);
-	    // throw !!
-	}
-	ContainerIndex<Indices...> const* t = this;
-	return PackNum<sizeof...(Indices)-1>::getIndexPtr(*t, n);
-    }
-
-    
-    template <class... Indices>
-    size_t ContainerIndex<Indices...>::getStepSize(size_t n) const
-    {
-	if(n >= sizeof...(Indices)){
-	    assert(0);
-	    // throw !!
-	}
-	return mBlockSizes[n+1];
-    }
-	
-    template <class... Indices>
-    bool ContainerIndex<Indices...>::first() const
-    {
-	return IB::pos() == 0;
-    }
-
-    template <class... Indices>
-    bool ContainerIndex<Indices...>::last() const
-    {
-	return IB::pos() == IB::mRangePtr->size() - 1;
-    }
-    
     template <class... Indices>
     ContainerIndex<Indices...>& ContainerIndex<Indices...>::operator()(const std::shared_ptr<Indices>&... inds)
     {
@@ -314,12 +278,6 @@ namespace MultiArrayTools
 	return sync();
     }
 
-    template <class... Indices>
-    std::shared_ptr<typename ContainerIndex<Indices...>::RangeType> ContainerIndex<Indices...>::range() const
-    {
-	return std::dynamic_pointer_cast<RangeType>( IB::mRangePtr );
-    }
-    
     /*****************************
      *   ContainerRangeFactory   *
      *****************************/
@@ -408,11 +366,12 @@ namespace MultiArrayTools
     }
     
     template <class... Ranges>
-    std::shared_ptr<IndexBase> ContainerRange<Ranges...>::index() const
+    std::shared_ptr<VIWB> ContainerRange<Ranges...>::index() const
     {
-	return std::make_shared<ContainerIndex<typename Ranges::IndexType...> >
-	    ( std::dynamic_pointer_cast<ContainerRange<Ranges...> >
-	      ( std::shared_ptr<RangeBase>( RB::mThis ) ) );
+	return std::make_shared<VIWB>
+	    ( std::make_shared<ContainerIndex<typename Ranges::IndexType...> >
+	      ( std::dynamic_pointer_cast<ContainerRange<Ranges...> >
+		( std::shared_ptr<RangeBase>( RB::mThis ) ) ) );
     }
     
 } // end namespace MultiArrayTools
diff --git a/src/index_base.h b/src/index_base.h
index 7d15ae3..53ecdb0 100644
--- a/src/index_base.h
+++ b/src/index_base.h
@@ -35,12 +35,11 @@ namespace MultiArrayTools
 	virtual size_t pos() const = 0;
 	virtual size_t max() const = 0;
 	virtual std::shared_ptr<RangeBase> rangePtr() const = 0;
-	virtual VirtualIndexWrapperBase getPtr(size_t n) const = 0;
+	virtual std::shared_ptr<VirtualIndexWrapperBase> getPtr(size_t n) const = 0;
 	virtual intptr_t getPtrNum() const = 0;
+	virtual size_t getStepSize(size_t n) const = 0;
     };
 
-    typedef VirtualIndexWrapperBase VIWB;
-
     template <class I>
     std::shared_ptr<IndexWrapper<I> > make_viwb(std::shared_ptr<I> idxPtr)
     {
@@ -68,7 +67,8 @@ namespace MultiArrayTools
 	virtual size_t max() const override { return mIdxPtr->max(); }
 	virtual std::shared_ptr<RangeBase> rangePtr() const override { return mIdxPtr->rangePtr(); }
 	virtual std::shared_ptr<VirtualIndexWrapperBase> getPtr(size_t n) const override { return mIdxPtr->getv(n); }
-	virtual intptr_t getPtrNum() const override { return static_cast<intptr_t>( mIdxPtr.get() ); };
+	virtual intptr_t getPtrNum() const override { return static_cast<intptr_t>( mIdxPtr.get() ); }
+	virtual size_t getStepSize(size_t n) const override { return mIdxPtr->getStepSize(n); }
 	
     private:
 	std::shared_ptr<I> mIdxPtr;
@@ -78,9 +78,12 @@ namespace MultiArrayTools
     class IndexInterface
     {
     public:
+	typedef typename I::RangeType RangeType;
+	
 	//DEFAULT_MEMBERS(IndexInterface);
 
 	I* THIS() { return static_cast<I*>(this); }
+	I const* THIS() const { return static_cast<I const*>(this); }
 	
 	~IndexInterface() = default; 
 
@@ -103,7 +106,8 @@ namespace MultiArrayTools
 	bool last() const { return I::S_last(THIS()); }
 	bool first() const { return I::S_first(THIS()); }
 
-	std::shared_ptr<RangeBase> rangePtr() const;
+	std::shared_ptr<RangeBase> vrange() const { return mRangePtr; }
+	std::shared_ptr<RangeType> range() const { return std::dynamic_pointer_cast<RangeType>(mRangePtr); }
 	
 	template <size_t N>
 	auto getPtr() const -> decltype(I::S_get<N>(THIS())) { return I::S_get<N>(THIS()); }
@@ -118,9 +122,12 @@ namespace MultiArrayTools
 
 	MetaType meta() const { return I::S_meta(THIS()); }
 	IndexInterface& at(const MetaType& meta) { return I::S_at(THIS(), meta); }
-	
-    protected:
 
+	
+    private:
+
+	friend I;
+	
 	IndexInterface() { mId = indexId(); }
 	IndexInterface(IndexInterface&& in) = default;
 	IndexInterface& operator=(IndexInterface&& in) = default;
@@ -130,7 +137,7 @@ namespace MultiArrayTools
 	std::shared_ptr<RangeBase> mRangePtr;
 	size_t mPos;
 	size_t mId;
-	
+	size_t mMax;
     };
    
 }
@@ -141,14 +148,15 @@ namespace MultiArrayTools
 
 namespace MultiArrayTools
 {
-    /*****************
+    /**********************
      *   IndexInterface   *
-     *****************/
+     **********************/
 
     template <class I, typename MetaType>
     IndexInterface<I,MetaType>::IndexInterface(const std::shared_ptr<RangeBase>& range,
 			 size_t pos) : mRangePtr(range),
-				       mPos(pos)
+				       mPos(pos),
+				       mMax(mRangePtr->size())
     {
 	mId = indexId();
     }
@@ -174,13 +182,7 @@ namespace MultiArrayTools
     template <class I, typename MetaType>
     size_t IndexInterface<I,MetaType>::max() const
     {
-	return mRangePtr->size();
-    }
-
-    template <class I, typename MetaType>
-    std::shared_ptr<RangeBase> IndexInterface<I,MetaType>::rangePtr() const
-    {
-	return mRangePtr;
+	return mMax;
     }
 
     template <class I, typename MetaType>
diff --git a/src/multi_array_operation.h b/src/multi_array_operation.h
index 9daf13e..93122a1 100644
--- a/src/multi_array_operation.h
+++ b/src/multi_array_operation.h
@@ -56,36 +56,7 @@ namespace MultiArrayTools
     template <class OpClass>
     std::shared_ptr<VIWB> seekBlockIndex(std::shared_ptr<VIWB> ownIdx,
 					 const OpClass& second);
-    /*
-    template <typename T>
-    class OperationBase
-    {
-    public:
-	typedef T value_type;
 
-	OperationBase() = default;
-	virtual ~OperationBase() = default;
-
-	 // init block, return resulting type (BLOCK, VALUE, SPLIT)
-	virtual std::vector<BTSS> block(const std::shared_ptr<IndexBase> blockIndex) const = 0;
-	virtual const OperationBase& block() const = 0; // update block
-	
-	//virtual size_t argNum() const = 0;
-	virtual const Block<T>& get() const = 0;
-    };
-   
-    template <typename T>
-    class MutableOperationBase : public OperationBase<T>
-    {
-    public:
-	typedef T value_type;
-	
-	MutableOperationBase() = default;
-
-	virtual MBlock<T>& get() = 0;
-
-    };
-    */
     template <typename T, class OperationClass>
     class OperationTemplate
     {
@@ -333,7 +304,7 @@ namespace MultiArrayTools
 	return out;
     }
 
-    void minimizeAppearanceOfType(std::map<std::shared_ptr<IndexBase>, std::vector<BTSS> >& mp,
+    void minimizeAppearanceOfType(std::map<std::shared_ptr<VIWB>, std::vector<BTSS> >& mp,
 				  BlockType bt)
     {
 	size_t minNum = getBTNum( mp.begin()->second, bt );
@@ -357,12 +328,12 @@ namespace MultiArrayTools
     }
     
     template <class OpClass>
-    std::shared_ptr<IndexBase> seekBlockIndex(std::shared_ptr<IndexBase> ownIdx,
-					      const OpClass& second)
+    std::shared_ptr<VIWB> seekBlockIndex(std::shared_ptr<VIWB> ownIdx,
+					 const OpClass& second)
     {
-	std::vector<std::shared_ptr<IndexBase> > ivec;
+	std::vector<std::shared_ptr<VIWB> > ivec;
 	seekIndexInst(ownIdx, ivec);
-	std::map<std::shared_ptr<IndexBase>, std::vector<BTSS> > mp;
+	std::map<std::shared_ptr<VIWB>, std::vector<BTSS> > mp;
 	
 	for(auto& xx: ivec){
 	    mp[xx] = second.block(xx);
@@ -465,7 +436,7 @@ namespace MultiArrayTools
     }
 
     template <typename T, class OpClass, class... Ranges>
-    std::vector<BTSS> OperationMaster<T,OpClass,Ranges...>::block(const std::shared_ptr<IndexBase> blockIndex) const
+    std::vector<BTSS> OperationMaster<T,OpClass,Ranges...>::block(const std::shared_ptr<VIWB> blockIndex) const
     {
 	std::vector<BTSS> btv(1, getBlockType(mIndex, blockIndex, true) );
 	mBlockPtr = makeBlock(mArrayRef.datav(), btv[0].second, blockIndex->max());
@@ -501,7 +472,7 @@ namespace MultiArrayTools
     }
 
     template <typename T, class... Ranges>
-    std::vector<BTSS> ConstOperationRoot<T,Ranges...>::block(const std::shared_ptr<IndexBase> blockIndex) const
+    std::vector<BTSS> ConstOperationRoot<T,Ranges...>::block(const std::shared_ptr<VIWB> blockIndex) const
     {
 	std::vector<BTSS> btv(1, getBlockType(mIndex, blockIndex, true) );
 	mBlockPtr = makeBlock(mArrayRef.datav(), btv[0].second, blockIndex->max());
@@ -551,7 +522,7 @@ namespace MultiArrayTools
     }
 
     template <typename T, class... Ranges>
-    std::vector<BTSS> OperationRoot<T,Ranges...>::block(const std::shared_ptr<IndexBase> blockIndex) const
+    std::vector<BTSS> OperationRoot<T,Ranges...>::block(const std::shared_ptr<VIWB> blockIndex) const
     {
 	std::vector<BTSS> btv(1, getBlockType(mIndex, blockIndex, true) );
 	mBlockPtr = makeBlock(mArrayRef.datav(), btv[0].second, blockIndex->max());
@@ -582,7 +553,7 @@ namespace MultiArrayTools
     }
 
     template <typename T, class OpFunction, class... Ops>
-    std::vector<BTSS> Operation<T,OpFunction,Ops...>::block(const std::shared_ptr<IndexBase> blockIndex) const
+    std::vector<BTSS> Operation<T,OpFunction,Ops...>::block(const std::shared_ptr<VIWB> blockIndex) const
     {
 	std::vector<BTSS> btv;
 	PackNum<sizeof...(Ops)-1>::makeBlockTypeVec(btv, mOps, blockIndex);
@@ -617,7 +588,7 @@ namespace MultiArrayTools
     }
     
     template <typename T, class Op, class IndexType>
-    std::vector<BTSS> Contraction<T,Op,IndexType>::block(const std::shared_ptr<IndexBase> blockIndex) const
+    std::vector<BTSS> Contraction<T,Op,IndexType>::block(const std::shared_ptr<VIWB> blockIndex) const
     {
 	return mOp.block(blockIndex);
     }
diff --git a/src/multi_range.h b/src/multi_range.h
index ecfe670..6ecf09d 100644
--- a/src/multi_range.h
+++ b/src/multi_range.h
@@ -15,24 +15,32 @@
 
 namespace MultiArrayTools
 {
+    namespace
+    {
+	using namespace MultiArrayHelper;
+    }
     
     template <class... Indices>
-    class MultiIndex : public IndexInterface<std::tuple<typename Indices::MetaType...> >
+    class MultiIndex : public IndexInterface<MultiIndex<Indices...>,
+					     std::tuple<typename Indices::MetaType...> >
     {
     public:
 	
-	typedef IndexBase IB;
+	typedef IndexInterface<MultiIndex<Indices...>,
+			       std::tuple<typename Indices::MetaType...> > IB;
 	typedef std::tuple<std::shared_ptr<Indices>...> IndexPack;
 	typedef std::tuple<typename Indices::MetaType...> MetaType;
-	typedef IndexInterface<MetaType> IndexI;	
 	typedef MultiRange<typename Indices::RangeType...> RangeType;
 	
-    protected:
+    private:
+	
 	IndexPack mIPack;
 	std::array<size_t,sizeof...(Indices)+1> mBlockSizes;
-	
+
     public:
+
 	MultiIndex() = delete;
+	
 	// NO DEFAULT HERE !!!
 	// ( have to assign sub-indices (ptr!) correctly )
 	//MultiIndex(const MultiIndex& in);
@@ -42,50 +50,119 @@ namespace MultiArrayTools
 	template <class MRange>
 	MultiIndex(const std::shared_ptr<MRange>& range);
 
-	virtual IndexType type() const override;
-	
-	virtual MultiIndex& operator++() override;
-	virtual MultiIndex& operator--() override;
-	virtual MultiIndex& operator=(size_t pos) override;
-
-	virtual int pp(std::shared_ptr<IndexBase>& idxPtr) override;
-	virtual int mm(std::shared_ptr<IndexBase>& idxPtr) override;
-	
 	template <size_t DIR>
 	MultiIndex& up();
 
 	template <size_t DIR>
 	MultiIndex& down();
-	
+
 	template <size_t N>
 	auto get() const -> decltype( *std::get<N>( mIPack ) )&;
 
-	template <size_t N>
-	auto getPtr() const -> decltype( std::get<N>( mIPack ) )&;
-	
-	const IndexBase& get(size_t n) const;
-	virtual std::shared_ptr<IndexBase> getPtr(size_t n) const override;
-	virtual size_t getStepSize(size_t n) const override;
-	
-        virtual MetaType meta() const override;
-	virtual MultiIndex& at(const MetaType& metaPos) override;
-
-	virtual bool first() const override;
-	virtual bool last() const override;
-	
-	virtual size_t dim() const override;
-
-	std::shared_ptr<RangeType> range() const;
-
-	//virtual MultiIndex& lock(std::shared_ptr<IndexBase>& idx) override;
-	
 	// raplace instances (in contrast to its analogon in ContainerIndex
 	// MultiIndices CANNOT be influences be its subindices, so there is
 	// NO foreign/external controll)
 	// Do NOT share index instances between two or more MultiIndex instances
 	MultiIndex& operator()(std::shared_ptr<Indices>&... indices);
 	
-	virtual std::string id() const override { return std::string("mul") + std::to_string(IB::mId); }
+    private:
+
+	friend IB;
+	// ==== >>>>> STATIC POLYMORPHISM <<<<< ====
+	
+	static IndexType S_type(MultiIndex* i) { return IndexType::MULTI; }
+
+	static MultiIndex& S_ass_op(MultiIndex* i, size_t pos)
+	{
+	    i->mPos = pos;
+	    PackNum<sizeof...(Indices)-1>::setIndexPack(i->mIPack, pos);
+	    return *i;
+	}
+
+	static MultiIndex& S_pp_op(MultiIndex* i)
+	{
+	    PackNum<sizeof...(Indices)-1>::pp( i->mIPack );
+	    ++i->mPos;
+	    return *i;
+	}
+
+	static MultiIndex& S_mm_op(MultiIndex* i)
+	{
+	    PackNum<sizeof...(Indices)-1>::mm( i->mIPack );
+	    --i->mPos;
+	    return *i;
+	}
+
+	static int S_pp(MultiIndex* i, intptr_t idxPtrNum)
+	{
+	    int tmp = PackNum<sizeof...(Indices)-1>::pp(i->mIPack, i->mBlockSizes, idxPtrNum);
+	    i->mPos += tmp;
+	    return tmp;
+	}
+
+	static int S_mm(MultiIndex* i, intptr_t idxPtrNum)
+	{
+	    int tmp = PackNum<sizeof...(Indices)-1>::mm(i->mIPack, i->mBlockSizes, idxPtrNum);
+	    i->mPos -= tmp;
+	    return tmp;
+	}
+
+	static MetaType S_meta(MultiIndex* i)
+	{
+	    MetaType metaTuple;
+	    PackNum<sizeof...(Indices)-1>::getMetaPos(metaTuple, i->mIPack);
+	    return metaTuple;
+	}
+
+	static MultiIndex& S_at(MultiIndex* i, const MetaType& metaPos)
+	{
+	    PackNum<sizeof...(Indices)-1>::setMeta(i->mIPack, metaPos);
+	    i->mPos = PackNum<sizeof...(Indices)-1>::makePos(i->mIPack);
+	    return *i;
+	}
+	
+	static size_t S_dim(MultiIndex* i)
+	{
+	    return sizeof...(Indices);
+	}
+
+	static bool S_first(MultiIndex* i)
+	{
+	    return i->mPos == 0;
+	}
+
+	static bool S_last(MultiIndex* i)
+	{
+	    return i->mPos == i->mMax - 1;
+	}
+
+	template <size_t N>
+	static auto S_getPtr(MultiIndex* i) -> decltype( std::get<N>( mIPack ) )&
+	{
+	    return std::get<N>(i->mIPack);
+	}
+	
+	//const IndexBase& get(size_t n);
+	static std::shared_ptr<VIWB> S_getVPtr(MultiIndex* i, size_t n)
+	{
+	    if(n >= sizeof...(Indices)){
+		assert(0);
+		// throw !!
+	    }
+	    MultiIndex<Indices...> const* t = i;
+	    return PackNum<sizeof...(Indices)-1>::getIndexPtr(*t, n);
+	}
+	
+	static size_t S_getStepSize(MultiIndex* i, size_t n)
+	{
+	    if(n >= sizeof...(Indices)){
+		assert(0);
+		// throw !!
+	    }
+	    return i->mBlockSizes[n+1];
+	}
+
+	static std::string S_id(MultiIndex* i) { return std::string("mul") + std::to_string(IB::mId); }
     };
 
     /*************************
@@ -146,7 +223,7 @@ namespace MultiArrayTools
 	virtual IndexType begin() const override;
 	virtual IndexType end() const override;
 
-	virtual std::shared_ptr<IndexBase> index() const override;
+	virtual std::shared_ptr<VIWB> index() const override;
 
 	friend MultiRangeFactory<Ranges...>;
 	
@@ -199,7 +276,7 @@ namespace MultiArrayTools
     template <class... Indices>
     template <class MRange>
     MultiIndex<Indices...>::MultiIndex(const std::shared_ptr<MRange>& range) :
-	IndexInterface<std::tuple<typename Indices::MetaType...> >(range, 0)
+	IndexInterface<MultiIndex<Indices...>,std::tuple<typename Indices::MetaType...> >(range, 0)
     {
 	PackNum<sizeof...(Indices)-1>::construct(mIPack, *range);
 	IB::mPos = PackNum<sizeof...(Indices)-1>::makePos(mIPack);
@@ -207,52 +284,6 @@ namespace MultiArrayTools
 	PackNum<sizeof...(Indices)-1>::initBlockSizes(mBlockSizes, mIPack); // has one more element!
     }
 
-    template <class... Indices>
-    IndexType MultiIndex<Indices...>::type() const
-    {
-	return IndexType::MULTI;
-    }
-    
-    template <class... Indices>
-    MultiIndex<Indices...>& MultiIndex<Indices...>::operator++()
-    {
-	PackNum<sizeof...(Indices)-1>::pp( mIPack );
-	++IB::mPos;
-	return *this;
-    }
-
-    template <class... Indices>
-    MultiIndex<Indices...>& MultiIndex<Indices...>::operator--()
-    {
-	PackNum<sizeof...(Indices)-1>::mm( mIPack );
-	--IB::mPos;
-	return *this;
-    }
-    
-    template <class... Indices>
-    MultiIndex<Indices...>& MultiIndex<Indices...>::operator=(size_t pos)
-    {
-	IB::mPos = pos;
-	PackNum<sizeof...(Indices)-1>::setIndexPack(mIPack, pos);
-	return *this;
-    }
-
-    template <class... Indices>
-    int MultiIndex<Indices...>::pp(std::shared_ptr<IndexBase>& idxPtr)
-    {
-	int tmp = PackNum<sizeof...(Indices)-1>::pp(mIPack, mBlockSizes, idxPtr);
-	IB::mPos += tmp;
-	return tmp;
-    }
-
-    template <class... Indices>
-    int MultiIndex<Indices...>::mm(std::shared_ptr<IndexBase>& idxPtr)
-    {
-	int tmp = PackNum<sizeof...(Indices)-1>::mm(mIPack, mBlockSizes, idxPtr);
-	IB::mPos -= tmp;
-	return tmp;
-    }
-
     template <class... Indices>
     template <size_t DIR>
     MultiIndex<Indices...>& MultiIndex<Indices...>::up()
@@ -273,12 +304,6 @@ namespace MultiArrayTools
 	return *this;
     }
     
-    template <class... Indices>
-    size_t MultiIndex<Indices...>::dim() const
-    {
-	return sizeof...(Indices);
-    }
-    
     template <class... Indices>
     template <size_t N>
     auto MultiIndex<Indices...>::get() const -> decltype( *std::get<N>( mIPack ) )&
@@ -286,87 +311,6 @@ namespace MultiArrayTools
 	return *std::get<N>(mIPack);
     }
 
-    template <class... Indices>
-    template <size_t N>
-    auto MultiIndex<Indices...>::getPtr() const -> decltype( std::get<N>( mIPack ) )&
-    {
-	return std::get<N>(mIPack);
-    }
-    
-    template <class... Indices>
-    const IndexBase& MultiIndex<Indices...>::get(size_t n) const
-    {
-	if(n >= sizeof...(Indices)){
-	    assert(0);
-	    // throw !!
-	}
-	MultiIndex<Indices...> const* t = this;
-	return PackNum<sizeof...(Indices)-1>::getIndex(*t, n);
-    }
-
-    template <class... Indices>
-    std::shared_ptr<IndexBase> MultiIndex<Indices...>::getPtr(size_t n) const
-    {
-	if(n >= sizeof...(Indices)){
-	    assert(0);
-	    // throw !!
-	}
-	MultiIndex<Indices...> const* t = this;
-	return PackNum<sizeof...(Indices)-1>::getIndexPtr(*t, n);
-    }
-
-    template <class... Indices>
-    size_t MultiIndex<Indices...>::getStepSize(size_t n) const
-    {
-	if(n >= sizeof...(Indices)){
-	    assert(0);
-	    // throw !!
-	}
-	return mBlockSizes[n+1];
-    }
-    
-    template <class... Indices>
-    typename MultiIndex<Indices...>::MetaType MultiIndex<Indices...>::meta() const
-    {
-        MetaType metaTuple;
-	PackNum<sizeof...(Indices)-1>::getMetaPos(metaTuple, mIPack);
-	return metaTuple;
-    }
-
-    template <class... Indices>
-    MultiIndex<Indices...>& MultiIndex<Indices...>::at(const MultiIndex<Indices...>::MetaType& metaPos)
-    {
-	PackNum<sizeof...(Indices)-1>::setMeta(mIPack, metaPos);
-	IB::mPos = PackNum<sizeof...(Indices)-1>::makePos(mIPack);
-	return *this;
-    }
-
-    template <class... Indices>
-    bool MultiIndex<Indices...>::first() const
-    {
-	return IB::mPos == 0;
-    }
-
-    template <class... Indices>
-    bool MultiIndex<Indices...>::last() const
-    {
-	return IB::mPos == IB::mRangePtr->size() - 1;
-    }
-
-    template <class... Indices>
-    std::shared_ptr<typename MultiIndex<Indices...>::RangeType> MultiIndex<Indices...>::range() const
-    {
-	return std::dynamic_pointer_cast<RangeType>( IB::mRangePtr );
-    }
-    /*
-    template <class... Indices>
-    MultiIndex<Indices...>& MultiIndex<Indices...>::lock(std::shared_ptr<IndexBase>& idx)
-    {
-	IB::mLocked = (idx.get() == this);
-	PackNum<sizeof...(Indices)-1>::lock(mIPack, idx);
-	return *this;
-	}*/
-    
     template <class... Indices>
     MultiIndex<Indices...>& MultiIndex<Indices...>::operator()(std::shared_ptr<Indices>&... indices)
     {
@@ -467,11 +411,12 @@ namespace MultiArrayTools
     }
 
     template <class... Ranges>
-    std::shared_ptr<IndexBase> MultiRange<Ranges...>::index() const
+    std::shared_ptr<VIWB> MultiRange<Ranges...>::index() const
     {
-	return std::make_shared<MultiIndex<typename Ranges::IndexType...> >
-	    ( std::dynamic_pointer_cast<MultiRange<Ranges...> >
-	      ( std::shared_ptr<RangeBase>( RB::mThis ) ) );
+	return std::make_shared<VIWB>
+	    ( std::make_shared<MultiIndex<typename Ranges::IndexType...> >
+	      ( std::dynamic_pointer_cast<MultiRange<Ranges...> >
+		( std::shared_ptr<RangeBase>( RB::mThis ) ) ) );
     }
 }
 
diff --git a/src/pack_num.h b/src/pack_num.h
index 8fb37a4..bf9065e 100644
--- a/src/pack_num.h
+++ b/src/pack_num.h
@@ -90,10 +90,10 @@ namespace MultiArrayHelper
 	    auto& siPtr = std::get<N>(ip);
 	    //VCHECK(siPtr.id());
 	    if(static_cast<intptr_t>(siPtr.get()) == idxPtrNum){
-		return PackNum<N-1>::pp(ip, bs, idxPtrNum;
+		return PackNum<N-1>::pp(ip, bs, idxPtrNum);
 	    }
 	    else {
-		int tmp = siPtr->pp(idxPtr);
+		int tmp = siPtr->pp(idxPtrNum);
 		if(siPtr->pos() == siPtr->max()){
 		    (*siPtr) = 0;
 		    return PackNum<N-1>::pp(ip, bs, idxPtrNum) - siPtr->max() + 1;
@@ -233,7 +233,7 @@ namespace MultiArrayHelper
 	template <class... Ops>
 	static void makeBlockTypeVec(std::vector<std::pair<BlockType,size_t> >& btv,
 				     const std::tuple<Ops...>& ops,
-				     std::shared_ptr<IndexBase> idxPtr)
+				     std::shared_ptr<VIWB> idxPtr)
 	{
 	    auto subvec = std::move( std::get<N>(ops).block(idxPtr) );
 	    btv.insert(btv.end(), subvec.begin(), subvec.end() );
@@ -271,7 +271,7 @@ namespace MultiArrayHelper
 	}
 	*/
 	template <class IndexType>
-	static std::shared_ptr<IndexBase> getIndexPtr(const IndexType& in, size_t n)
+	static std::shared_ptr<VIWB> getIndexPtr(const IndexType& in, size_t n)
 	{
 	    return make_viwb( in.template get<0>() );
 	}
@@ -423,7 +423,7 @@ namespace MultiArrayHelper
 	template <class... Ops>
 	static void makeBlockTypeVec(std::vector<std::pair<BlockType,size_t> >& btv,
 				     const std::tuple<Ops...>& ops,
-				     std::shared_ptr<IndexBase> idxPtr)
+				     std::shared_ptr<VIWB> idxPtr)
 	{
 	    auto subvec = std::move( std::get<0>(ops).block(idxPtr) );
 	    btv.insert(btv.end(), subvec.begin(), subvec.end() );
diff --git a/src/single_range.h b/src/single_range.h
index 90f0193..785427b 100644
--- a/src/single_range.h
+++ b/src/single_range.h
@@ -19,7 +19,7 @@ namespace MultiArrayTools
     {
     public:
 
-	typedef IndexBase<SingleIndex<U,TYPE>,U> IB;
+	typedef IndexInterface<SingleIndex<U,TYPE>,U> IB;
 	typedef U MetaType;
 	typedef SingleRange<U,TYPE> RangeType;
 	
@@ -27,30 +27,87 @@ namespace MultiArrayTools
 	
 	SingleIndex(const std::shared_ptr<SingleRange<U,TYPE> >& range);
 
-	static IndexType S_type(SingleIndex* i) const;
-	
-	static SingleIndex& S_ass_op(SingleIndex* i, size_t pos);
-	static SingleIndex& S_pp_op(SingleIndex* i);
-	static SingleIndex& S_mm_op(SingleIndex* i);
+    private:
 
-	static int S_pp(SingleIndex* i, std::shared_ptr<VIWB>& idxPtr);
-	static int S_mm(SingleIndex* i, std::shared_ptr<VIWB>& idxPtr);
+	friend IB;
+
+	// ==== >>>>> STATIC POLYMORPHISM <<<<< ====
 	
-	static U S_meta(SingleIndex* i) const;
-	static SingleIndex& S_at(SingleIndex* i, const U& metaPos);
+	static IndexType S_type(SingleIndex* i)
+	{
+	    return IndexType::SINGLE;
+	}
 	
-	static size_t S_dim(SingleIndex* i) const; // = 1
-	static bool S_last(SingleIndex* i) const;
-	static bool S_first(SingleIndex* i) const;
+	static SingleIndex& S_ass_op(SingleIndex* i, size_t pos)
+	{
+	    i->mPos = pos;
+	    return *i;
+	}
+
+	static SingleIndex& S_pp_op(SingleIndex* i)
+	{
+	    ++i->mPos;
+	    return *i;
+	}
+
+	static SingleIndex& S_mm_op(SingleIndex* i)
+	{
+	    --i->mPos;
+	    return *i;
+	}
+
+	static int S_pp(SingleIndex* i, intptr_t idxPtrNum)
+	{
+	    ++(*i);
+	    return 1;
+	}
+
+	static int S_mm(SingleIndex* i, intptr_t idxPtrNum)
+	{
+	    --(*i);
+	    return 1;
+	}
+	
+	static U S_meta(SingleIndex* i)
+	{
+	    return std::dynamic_pointer_cast<SingleRange<U,TYPE> const>( i->mRangePtr )->get( i->pos() );
+	}
+
+	static SingleIndex& S_at(SingleIndex* i, const U& metaPos)
+	{
+	    operator=( std::dynamic_pointer_cast<SingleRange<U,TYPE> const>( i->mRangePtr )->getMeta( metaPos ) );
+	    return *i;
+	}
+	
+	static size_t S_dim(SingleIndex* i) // = 1
+	{
+	    return 1;
+	}
+
+	static bool S_last(SingleIndex* i)
+	{
+	    return i->mPos == i->mMax - 1;
+	}
+
+	static bool S_first(SingleIndex* i)
+	{
+	    return i->mPos == 0;
+	}
 
 	template <size_t N>
-	static void S_getPtr(SingleIndex* i) const;
+	static void S_getPtr(SingleIndex* i) {}
 
-	std::shared_ptr<VIWB> getVPtr(size_t n) const;
+	static std::shared_ptr<VIWB> S_getVPtr(SingleIndex* i, size_t n)
+	{
+	    return std::shared_ptr<VIWB>();
+	}
 	
-	static size_t S_getStepSize(SingleIndex* i, size_t n) const;
+	static size_t S_getStepSize(SingleIndex* i, size_t n)
+	{
+	    return 1;
+	}
 	
-	static std::string S_id(SingleIndex* i) const { return std::string("sin") + std::to_string(IB::mId); }
+	static std::string S_id(SingleIndex* i) { return std::string("sin") + std::to_string(IB::mId); }
     };
 
     template <typename U, RangeType TYPE>
@@ -109,98 +166,7 @@ namespace MultiArrayTools
 
     template <typename U, RangeType TYPE>
     SingleIndex<U,TYPE>::SingleIndex(const std::shared_ptr<SingleRange<U,TYPE> >& range) :
-	IndexInterface<U>(range, 0) {}
-
-    template <typename U, RangeType TYPE>
-    IndexType SingleIndex<U,TYPE>::S_type() const
-    {
-	return IndexType::SINGLE;
-    }
-	
-    template <typename U, RangeType TYPE>
-    SingleIndex<U,TYPE>& SingleIndex<U,TYPE>::S_ass_op(size_t pos)
-    {
-	IB::mPos = pos;
-	return *this;
-    }
-    
-    template <typename U, RangeType TYPE>
-    SingleIndex<U,TYPE>& SingleIndex<U,TYPE>::S_pp_op()
-    {
-	++IB::mPos;
-	return *this;
-    }
-
-    template <typename U, RangeType TYPE>
-    SingleIndex<U,TYPE>& SingleIndex<U,TYPE>::S_mm_op()
-    {
-	--IB::mPos;
-	return *this;
-    }
-
-    template <typename U, RangeType TYPE>
-    int SingleIndex<U,TYPE>::S_pp(std::shared_ptr<VIWB>& idxPtr)
-    {
-	++(*this);
-	return 1;
-    }
-
-    template <typename U, RangeType TYPE>
-    int SingleIndex<U,TYPE>::S_mm(std::shared_ptr<VIWB>& idxPtr)
-    {
-	--(*this);
-	return 1;
-    }
-    
-    template <typename U, RangeType TYPE>
-    U SingleIndex<U,TYPE>::S_meta() const
-    {
-	return std::dynamic_pointer_cast<SingleRange<U,TYPE> const>( IB::mRangePtr )->get( IB::pos() );
-    }
-
-    template <typename U, RangeType TYPE>
-    SingleIndex<U,TYPE>& SingleIndex<U,TYPE>::S_at(const U& metaPos)
-    {
-	operator=( std::dynamic_pointer_cast<SingleRange<U,TYPE> const>( IB::mRangePtr )->getMeta( metaPos ) );
-	return *this;
-    }
-
-    template <typename U, RangeType TYPE>
-    size_t SingleIndex<U,TYPE>::S_dim() const
-    {
-	return 1;
-    }
-
-    template <typename U, RangeType TYPE>
-    bool SingleIndex<U,TYPE>::S_last() const
-    {
-	return IB::mPos == IB::mRangePtr->size() - 1;
-    }
-
-    template <typename U, RangeType TYPE>
-    bool SingleIndex<U,TYPE>::S_first() const
-    {
-	return IB::mPos == 0;
-    }
-
-    template <typename U, RangeType TYPE>
-    template <size_t N>
-    void SingleIndex<U,TYPE>::S_getPtr() const
-    {
-	return;
-    }
-
-    template <typename U, RangeType TYPE>
-    std::shared_ptr<VIWB> SingleIndex<U,TYPE>::getVPtr(size_t n) const
-    {
-	return std::shared_ptr<VIWB>();
-    }
-    
-    template <typename U, RangeType TYPE>    
-    size_t SingleIndex<U,TYPE>::S_getStepSize(size_t n) const
-    {
-	return 1;
-    }
+	IndexInterface<SingleIndex<U,TYPE>,U>(range, 0) {}
     
     /********************
      *   SingleRange    *
@@ -282,8 +248,8 @@ namespace MultiArrayTools
     {
 	return std::make_shared<VIWB>
 	    ( std::make_shared<SingleIndex<U,TYPE> >
-	    ( std::dynamic_pointer_cast<SingleRange<U,TYPE> >
-	      ( std::shared_ptr<RangeBase>( RB::mThis ) ) ) );
+	      ( std::dynamic_pointer_cast<SingleRange<U,TYPE> >
+		( std::shared_ptr<RangeBase>( RB::mThis ) ) ) );
     }
 
 }