diff --git a/src/include/base/to_string.cc.h b/src/include/base/to_string.cc.h
index 2ac4878..dac3678 100644
--- a/src/include/base/to_string.cc.h
+++ b/src/include/base/to_string.cc.h
@@ -3,6 +3,7 @@
 #define __cxz_to_string_cc_h__
 
 #include "to_string.h"
+#include "iter.h"
 #include <sstream>
 
 namespace CNORXZ
@@ -29,7 +30,7 @@ namespace CNORXZ
     }
 
     template <typename T, size_t N>
-    String ToString<std::array<T,N>>::func(const std::array<T,N>& a)
+    String ToString<Arr<T,N>>::func(const Arr<T,N>& a)
     {
 	std::stringstream ss;
 	ss << "(";
@@ -41,6 +42,19 @@ namespace CNORXZ
 	return ss.str();
     }
 
+    template <typename... Ts>
+    String ToString<Tuple<Ts...>>::func(const Tuple<Ts...>& t)
+    {
+	const String blim = "(";
+	const String elim = ")";
+	const String dlim = ",";
+	return iter<1,sizeof...(Ts)>
+	    ( [&](auto i) { return toString(std::get<i>(t)); },
+	      [&](const auto&... xs) {
+		  return blim + toString(std::get<0>(t)) + ( (dlim + xs) + ... ) + elim;
+	      } );
+    }
+
     template <typename T>
     String toString(const T& a)
     {
diff --git a/src/include/base/to_string.h b/src/include/base/to_string.h
index 148ef1f..08f055b 100644
--- a/src/include/base/to_string.h
+++ b/src/include/base/to_string.h
@@ -30,6 +30,12 @@ namespace CNORXZ
 	static String func(const Arr<T,N>& a);
     };
 
+    template <typename... Ts>
+    struct ToString<Tuple<Ts...>>
+    {
+	static String func(const Tuple<Ts...>& t);
+    };
+    
     template <>
     struct ToString<DType>
     {
diff --git a/src/include/ranges/crange.h b/src/include/ranges/crange.h
index 354df24..8daf6c4 100644
--- a/src/include/ranges/crange.h
+++ b/src/include/ranges/crange.h
@@ -15,6 +15,7 @@ namespace CNORXZ
 
 	typedef IndexInterface<CIndex,SizeT> IB;
 	typedef CRange RangeType;
+	typedef SizeT MetaType;
 
 	CIndex(const RangePtr& range, SizeT pos = 0);
 	
@@ -63,7 +64,7 @@ namespace CNORXZ
 	RangePtr mRef;
     };
 
-    class CRange : public RangeInterface<CIndex,SizeT>
+    class CRange : public RangeInterface<CRange>
     {
     public:
 	typedef RangeBase RB;
diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 6c8442a..376a61e 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -3,8 +3,6 @@
 #define __cxz_mrange_cc_h__
 
 #include "mrange.h"
-#include "range_helper.h"
-#include "statics/static_for.h"
 
 namespace CNORXZ
 {
@@ -22,11 +20,13 @@ namespace CNORXZ
     }
     
     template <class... Indices>
-    constexpr decltype(auto) MIndex<Indices...>::mkBlockSizes() const
+    template <SizeT... Is>
+    constexpr decltype(auto) MIndex<Indices...>::mkBlockSizes(const IndexPack& ipack, Isq<Is...> is)
     {
 	return std::make_tuple
 	    ( iter<Is,NI>
-	      ( [&](auto i) { return std::get<i>(mIPack)->max(); },
+	      // replace UPos by SPos where possible !!!
+	      ( [&](auto i) { return UPos(std::get<i>(ipack)->max()); },
 		[&](const auto&... as) { return (as * ...); } )...,
 	      SPos<1>() );
     }
@@ -38,13 +38,13 @@ namespace CNORXZ
 	auto& i = std::get<I>(mIPack);
 	if constexpr(I != 0){
 	    if(i->pos() == i->max()-1){
-		IB::mPos -= std::get<I>(mBlockSize) * i->pos();
+		IB::mPos -= std::get<I>(mBlockSizes).val() * i->pos();
 		(*i) = 0;
-		upi<N-1>();
+		up<I-1>();
 		return;
 	    }
 	}
-	IB::mPos += std::get<I>(mBlockSize);
+	IB::mPos += std::get<I>(mBlockSizes).val();
 	++(*i);
     }
 
@@ -56,12 +56,12 @@ namespace CNORXZ
 	if constexpr(I != 0){
 	    if(i->pos() == 0){
 		(*i) = i->max()-1;
-		IB::mPos += std::get<I>(mBlockSize) * i->pos();
-		downi<N-1>();
+		IB::mPos += std::get<I>(mBlockSizes).val() * i->pos();
+		down<I-1>();
 		return;
 	    }
 	}
-	IB::mPos -= std::get<I>(mBlockSize);
+	IB::mPos -= std::get<I>(mBlockSizes).val();
 	--(*i);
     }
 
@@ -69,7 +69,7 @@ namespace CNORXZ
     template <SizeT I, class Xpr, class F>
     constexpr decltype(auto) MIndex<Indices...>::mkIFor(const Xpr& xpr, F&& f) const
     {
-	if constexpr(I == sizeof..(Indices)-1){
+	if constexpr(I == sizeof...(Indices)-1){
 	    return std::get<I>(mIPack)->ifor(xpr,f);
 	}
 	else {
@@ -85,27 +85,26 @@ namespace CNORXZ
     MIndex<Indices...>::MIndex(const MIndex& i) :
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(i.pos()),
 	mIPack(mkIPack(IB::mPos, Isqr<0,NI>{})),
-	mBlockSizes(mkBlockSizes(), Isqr<0,NI>{}),
-	mRange(i.range())
+	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{})),
+	mRange(rangeCast<RangeType>(i.range()))
     {}
 
     template <class... Indices>
-    MIndex& MIndex<Indices...>::operator=(const MIndex& i)
+    MIndex<Indices...>& MIndex<Indices...>::operator=(const MIndex& i)
     {
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>::operator=(i);
 	mIPack = mkIPack(IB::mPos, Isqr<0,NI>{});
-	mBlockSizes(mkBlockSizes(), Isqr<0,NI>{});
-	mRange = i.range();
+	mBlockSizes = mkBlockSizes(mIPack,Isqr<0,NI-1>{});
+	mRange = rangeCast<RangeType>(i.range());
 	return *this;
     }
 
     template <class... Indices>
-    template <class MRange>
-    MIndex<Indices...>::MIndex(const Sptr<MRange>& range, SizeT pos) :
+    MIndex<Indices...>::MIndex(const RangePtr& range, SizeT pos) :
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(0),
 	mIPack(mkIPack(IB::mPos, Isqr<0,NI>{})),
-	mBlockSizes(mkBlockSizes(), Isqr<0,NI>{}),
-	mRange(range),
+	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{})),
+	mRange(rangeCast<RangeType>(range))
     {
 	(*this) = pos;
     }
@@ -114,7 +113,7 @@ namespace CNORXZ
     MIndex<Indices...>& MIndex<Indices...>::operator=(SizeT pos)
     {
 	IB::mPos = pos;
-	iter<0,NI>( [&](auto i) { std::get<i>(mIPack) = (IB::mPos / std::get<i>(mBlockSize)) % std::get<i>(mIPack)->max() }, NoF{} );
+	iter<0,NI>( [&](auto i) { *std::get<i>(mIPack) = (IB::mPos / std::get<i>(mBlockSizes).val()) % std::get<i>(mIPack)->max(); }, NoF{} );
 	return *this;
     }
 
@@ -153,9 +152,9 @@ namespace CNORXZ
     }
 
     template <class... Indices>
-    MIndex& MIndex<Indices...>::operator+=(Int n)
+    MIndex<Indices...>& MIndex<Indices...>::operator+=(Int n)
     {
-	if(-n > IB::mPos){
+	if(-n > static_cast<long int>(IB::mPos)){
 	    (*this) = 0;
 	}
 	const SizeT p = IB::mPos + n;
@@ -167,9 +166,9 @@ namespace CNORXZ
     }
 
     template <class... Indices>
-    MIndex& MIndex<Indices...>::operator-=(Int n)
+    MIndex<Indices...>& MIndex<Indices...>::operator-=(Int n)
     {
-	if(n > IB::mPos){
+	if(n > static_cast<long int>(IB::mPos)){
 	    (*this) = 0;
 	}
 	const SizeT p = IB::mPos + n;
@@ -193,7 +192,7 @@ namespace CNORXZ
     }
 
     template <class... Indices>
-    MetaType MIndex<Indices...>::operator*() const
+    typename MIndex<Indices...>::MetaType MIndex<Indices...>::operator*() const
     {
 	return meta();
     }
@@ -205,25 +204,25 @@ namespace CNORXZ
     }	
 
     template <class... Indices>	
-    Sptr<RangeType> MIndex<Indices...>::range() const
+    Sptr<typename MIndex<Indices...>::RangeType> MIndex<Indices...>::range() const
     {
 	return mRange;
     }
 
     template <class... Indices>	
     template <SizeT I>
-    decltype(auto) MIndex<Indices...>::stepSize(const IndexId<I>& id) const;
+    decltype(auto) MIndex<Indices...>::stepSize(const IndexId<I>& id) const
     {
 	return iter<0,NI>
-	    ( [&](auto i) { return std::get<i>(mIPack)->stepSize(id) * std::get<i>(mBlockSize); },
+	    ( [&](auto i) { return std::get<i>(mIPack)->stepSize(id) * std::get<i>(mBlockSizes); },
 	      [](const auto&... ss) { return ( ss + ... ); });
     }
 
     template <class... Indices>
     String MIndex<Indices...>::stringMeta() const
     {
-	const String blim = "[";
-	const String elim = "]";
+	const String blim = "(";
+	const String elim = ")";
 	const String dlim = ",";
 	return iter<1,NI>
 	    ( [&](auto i) { return std::get<i>(mIPack)->stringMeta(); },
@@ -242,9 +241,9 @@ namespace CNORXZ
     template <class... Indices>
     MIndex<Indices...>& MIndex<Indices...>::at(const MetaType& metaPos)
     {
-	iter<0,NI>( [&](auto i) { std::get<Is>(mIPack)->at( std::get<Is>(meta) ) }, NoF {} );
+	iter<0,NI>( [&](auto i) { std::get<i>(mIPack)->at( std::get<i>(metaPos) ); }, NoF {} );
 	IB::mPos = iter<0,NI>
-	    ( [&](auto i) { return std::get<i>(mIPack)*std::get<i>(mBlockSizes); },
+	    ( [&](auto i) { return std::get<i>(mIPack)->pos()*std::get<i>(mBlockSizes).val(); },
 	      [](const auto&... xs) { return (xs + ...); });
 	return *this;
     }
@@ -261,19 +260,19 @@ namespace CNORXZ
     {
 	mIPack = mi.mIPack;
 	IB::mPos = iter<0,NI>
-	    ( [&](auto i) { return std::get<i>(mIPack)*std::get<i>(mBlockSizes); },
+	    ( [&](auto i) { return std::get<i>(mIPack)->pos()*std::get<i>(mBlockSizes).val(); },
 	      [](const auto&... xs) { return (xs + ...); });
 	return *this;
     }
 
     template <class... Indices>
-    const IndexPack& pack() const
+    const typename MIndex<Indices...>::IndexPack& MIndex<Indices...>::pack() const
     {
 	return mIPack;
     }
 
     template <class... Indices>
-    const auto& blockSizes() const
+    const auto& MIndex<Indices...>::blockSizes() const
     {
 	return mBlockSizes;
     }
@@ -298,14 +297,14 @@ namespace CNORXZ
     template <class... Ranges>
     void MRangeFactory<Ranges...>::make()
     {
-	auto info = typeid(MRange<Ranges...>);
+	const auto& info = typeid(MRange<Ranges...>);
 	if(mRef != nullptr) {
-	    mProd = this->fromCreated[info.hash_code()][mRef->id()];
+	    mProd = this->fromCreated(info, {mRef->id()});
 	}
 	if(mProd == nullptr) {
 	    RangePtr key = mProd = std::shared_ptr<MRange<Ranges...>>
-		( new MRange<Ranges...>( mSpace ) );
-	    if(mRef != nullptr) { key = mRef }
+		( new MRange<Ranges...>( mRs ) );
+	    if(mRef != nullptr) { key = mRef; }
 	    this->addToCreated(info, { key->id() }, mProd);
 	}
     }
@@ -317,7 +316,7 @@ namespace CNORXZ
     template <class... Ranges>
     MRange<Ranges...>::MRange(const Tuple<Sptr<Ranges>...>& rs) :
 	mRs(rs),
-	mA( mkA( std::make_index_sequence<NR>{} ) )
+	mA( mkA() )
     {}
 
     template <class... Ranges>
@@ -330,7 +329,7 @@ namespace CNORXZ
     template <class... Ranges>
     SizeT MRange<Ranges...>::size() const
     {
-	return iter<0,NR>( [&](auto i) { return std::get<i>(mRs)->size() },
+	return iter<0,NR>( [&](auto i) { return std::get<i>(mRs)->size(); },
 			   [](const auto&... xs) { return (xs * ...); } );
     }
 
@@ -343,7 +342,19 @@ namespace CNORXZ
     template <class... Ranges>
     String MRange<Ranges...>::stringMeta(SizeT pos) const
     {
-	return (begin()+pos).stringMeta();
+	return (this->begin()+pos).stringMeta();
+    }
+
+    template <class... Ranges>
+    const TypeInfo& MRange<Ranges...>::type() const
+    {
+	return typeid(MRange<Ranges...>);
+    }
+    
+    template <class... Ranges>
+    const TypeInfo& MRange<Ranges...>::metaType() const
+    {
+	return typeid(MetaType);
     }
 
     template <class... Ranges>
@@ -353,15 +364,15 @@ namespace CNORXZ
     }
 
     template <class... Ranges>
-    const MetaType MRange<Ranges...>::get(SizeT pos) const
+    const typename MRange<Ranges...>::MetaType MRange<Ranges...>::get(SizeT pos) const
     {
-	return (begin()+pos)->meta();
+	return (this->begin()+pos)->meta();
     }
 
     template <class... Ranges>
     SizeT MRange<Ranges...>::getMeta(const MetaType& metaPos) const
     {
-	auto i = begin();
+	auto i = this->begin();
 	return i.at(metaPos).pos();
     }
 
@@ -372,8 +383,18 @@ namespace CNORXZ
     template <class... Ranges>
     decltype(auto) MRange<Ranges...>::mkA() const
     {
-	return iter<0,NR>([&](auto i) { return std::get<Is>(mRs); },
-			  [](const auto&... xs) { return Arr<RangePtr,NR> { xs... } } );
+	return iter<0,NR>([&](auto i) { return std::get<i>(mRs); },
+			  [](const auto&... xs) { return Arr<RangePtr,NR> { xs... }; } );
+    }
+
+    /****************************
+     *   non-member functions   *
+     ****************************/
+
+    template <class... Ranges>
+    RangePtr mrange(const Sptr<Ranges>&... rs)
+    {
+	return MRangeFactory<Ranges...>(std::make_tuple(rs...)).create();
     }
     
 }
diff --git a/src/include/ranges/mrange.h b/src/include/ranges/mrange.h
index 1b0437a..a4a2e80 100644
--- a/src/include/ranges/mrange.h
+++ b/src/include/ranges/mrange.h
@@ -28,8 +28,8 @@ namespace CNORXZ
 	// ( have to assign sub-indices (ptr!) correctly )
 	MIndex() = default;
 	MIndex(const MIndex& i);
-	MIndex(MIndex&& i);
-	MIndex& operator=(const MIndex& i) = default;
+	MIndex& operator=(const MIndex& i);
+	MIndex(MIndex&& i) = default;
 	MIndex& operator=(MIndex&& i) = default;
 
 	MIndex(const RangePtr& range, SizeT pos = 0);
@@ -47,7 +47,7 @@ namespace CNORXZ
 
 	MetaType operator*() const;
 
-	SizeT dim() const
+	SizeT dim() const;
 	Sptr<RangeType> range() const;
 
 	template <SizeT I>
@@ -67,16 +67,12 @@ namespace CNORXZ
 	const auto& blockSizes() const;
 
     private:
-	IndexPack mIPack;
-	typedef decltype(mkBlockSizes(Isqr<0,NI-1>{})) BlockTuple;
-	BlockTuple mBlockSizes;
-	Sptr<RangeType> mRange;
+	template <SizeT... Is>
+	static constexpr decltype(auto) mkBlockSizes(const IndexPack& ipack, Isq<Is...> is);
 
 	template <SizeT... Is>
 	constexpr decltype(auto) mkIPack(SizeT pos, Isq<Is...> is) const;
 
-	constexpr decltype(auto) mkBlockSizes() const;
-
 	template <SizeT I>
 	inline void up();
 
@@ -85,6 +81,11 @@ namespace CNORXZ
 
 	template <SizeT I, class Xpr, class F>
 	constexpr decltype(auto) mkIFor(const Xpr& xpr, F&& f) const;
+
+	IndexPack mIPack;
+	typedef RemoveRef<decltype(mkBlockSizes(mIPack,Isqr<0,NI-1>{}))> BlockTuple;
+	BlockTuple mBlockSizes;
+	Sptr<RangeType> mRange;
     };
 
     // modified blockSizes; to be used for Slices; can be created from MIndices
@@ -123,8 +124,7 @@ namespace CNORXZ
     };
     
     template <class... Ranges>
-    class MRange : public RangeInterface<MIndex<typename Ranges::IndexType...>,
-					 Tuple<typename Ranges::IndexType::MetaType...>>
+    class MRange : public RangeInterface<MRange<Ranges...>>
     {
     public:
 	typedef RangeBase RB;
@@ -138,8 +138,8 @@ namespace CNORXZ
 	virtual SizeT size() const override final;
 	virtual SizeT dim() const override final;
 	virtual String stringMeta(SizeT pos) const override final;
-	virtual IndexType begin() const override final;
-	virtual IndexType end() const override final;
+	virtual const TypeInfo& type() const override final;
+	virtual const TypeInfo& metaType() const override final;
 	
 	decltype(auto) space() const;
 	const MetaType get(SizeT pos) const;
@@ -157,7 +157,9 @@ namespace CNORXZ
 
 	decltype(auto) mkA() const;
     };
-    
+
+    template <class... Ranges>
+    RangePtr mrange(const Sptr<Ranges>&... rs);
 }
 
 #endif
diff --git a/src/include/ranges/range_base.cc.h b/src/include/ranges/range_base.cc.h
index a66abf2..8c80a4f 100644
--- a/src/include/ranges/range_base.cc.h
+++ b/src/include/ranges/range_base.cc.h
@@ -4,25 +4,30 @@
 
 #include "range_base.h"
 #include "dindex.h"
+#include "mrange.h"
 
 namespace CNORXZ
 {
-    template <class Index, typename Meta>
-    Index RangeInterface<Index,Meta>::begin() const
+    template <class Range>
+    decltype(auto) RangeInterface<Range>::begin() const
     {
-	return Index(RangePtr(RB::mThis), 0);
+	typedef typename Range::IndexType IndexType;
+	return IndexType(RangePtr(RB::mThis), 0);
     }
 
-    template <class Index, typename Meta>
-    Index RangeInterface<Index,Meta>::end() const
+    template <class Range>
+    decltype(auto) RangeInterface<Range>::end() const
     {
-	return Index(RangePtr(RB::mThis), this->size());
+	typedef typename Range::IndexType IndexType;
+	return IndexType(RangePtr(RB::mThis), this->size());
     }
 
-    template <class Index, typename Meta>
-    DIndex RangeInterface<Index,Meta>::index(SizeT pos) const
+    template <class Range>
+    DIndex RangeInterface<Range>::index(SizeT pos) const
     {
-	return XIndexPtr(std::make_shared<XIndex<Index,Meta>>( this->begin()+pos ));
+	typedef typename Range::IndexType IndexType;
+	typedef typename IndexType::MetaType MetaType;
+	return XIndexPtr(std::make_shared<XIndex<IndexType,MetaType>>( this->begin()+pos ));
     }
 	
     template <class Range>
diff --git a/src/include/ranges/range_base.h b/src/include/ranges/range_base.h
index a4d91df..96c4a29 100644
--- a/src/include/ranges/range_base.h
+++ b/src/include/ranges/range_base.h
@@ -45,7 +45,7 @@ namespace CNORXZ
 	
 	virtual ~RangeBase() = default;
 
-	virtual RangePtr sub() const;
+	virtual RangePtr sub(SizeT num) const;
 	virtual SizeT size() const = 0;
 	virtual SizeT dim() const = 0;
 	virtual const TypeInfo& type() const = 0;
@@ -72,16 +72,15 @@ namespace CNORXZ
 	RangePtr mRel; // used, if created from another range, to point on it
     };
 
-    template <class Index, typename Meta>
+    template <class Range>
     class RangeInterface : public RangeBase
     {
     public:
 
-	typedef Index IndexType;
 	typedef RangeBase RB;
 	
-	Index begin() const;
-	Index end() const;
+	decltype(auto) begin() const;
+	decltype(auto) end() const;
 	virtual DIndex index(SizeT pos) const override final;
 
     protected:
@@ -97,7 +96,8 @@ namespace CNORXZ
     template <class Range>
     Sptr<Range> rangeCast(const RangePtr r);
 
-    RangePtr operator*(const RangePtr& a, const RangePtr& b); // -> Ptr to MultiRange
+    RangePtr operator*(const RangePtr& a, const RangePtr& b); // -> Ptr to YRange
+
 }
 
 #endif
diff --git a/src/include/ranges/ranges.cc.h b/src/include/ranges/ranges.cc.h
index 606acb6..fc79abd 100644
--- a/src/include/ranges/ranges.cc.h
+++ b/src/include/ranges/ranges.cc.h
@@ -1,6 +1,7 @@
 
 #include "index_base.cc.h"
 #include "range_base.cc.h"
+#include "mrange.cc.h"
 #include "xindex.cc.h"
 #include "urange.cc.h"
 #include "crange.cc.h"
diff --git a/src/include/ranges/ranges.h b/src/include/ranges/ranges.h
index 3aa6ea2..b9a799f 100644
--- a/src/include/ranges/ranges.h
+++ b/src/include/ranges/ranges.h
@@ -1,7 +1,7 @@
 
 #include "range_base.h"
 #include "index_base.h"
-//#include "mrange.h"
+#include "mrange.h"
 //#include "range_helper.h"
 #include "crange.h"
 //#include "subrange.h"
diff --git a/src/include/ranges/urange.cc.h b/src/include/ranges/urange.cc.h
index 1d1c46c..91e3926 100644
--- a/src/include/ranges/urange.cc.h
+++ b/src/include/ranges/urange.cc.h
@@ -172,7 +172,7 @@ namespace CNORXZ
     
     template <typename MetaType>
     URange<MetaType>::URange(const Vector<MetaType>& space) :
-	RangeInterface<URange<MetaType>,MetaType>(),
+	RangeInterface<URange<MetaType>>(),
 	mSpace(space)
     {
 	std::sort(mSpace.begin(), mSpace.end(), std::less<MetaType>());
@@ -182,7 +182,7 @@ namespace CNORXZ
 
     template <typename MetaType>
     URange<MetaType>::URange(Vector<MetaType>&& space) :
-	RangeInterface<UIndex<MetaType>,MetaType>(),
+	RangeInterface<URange<MetaType>>(),
 	mSpace(space)
     {
 	std::sort(mSpace.begin(), mSpace.end(), std::less<MetaType>());
diff --git a/src/include/ranges/urange.h b/src/include/ranges/urange.h
index 9543b94..35fb4da 100644
--- a/src/include/ranges/urange.h
+++ b/src/include/ranges/urange.h
@@ -11,13 +11,14 @@
 namespace CNORXZ
 {
     
-    template <typename MetaType>
-    class UIndex : public IndexInterface<UIndex<MetaType>,MetaType>
+    template <typename MetaT>
+    class UIndex : public IndexInterface<UIndex<MetaT>,MetaT>
     {
     public:
 
-	typedef IndexInterface<UIndex<MetaType>,MetaType> IB;
-	typedef URange<MetaType> RangeType;
+	typedef IndexInterface<UIndex<MetaT>,MetaT> IB;
+	typedef URange<MetaT> RangeType;
+	typedef MetaT MetaType;
 
 	UIndex(const RangePtr& range, SizeT pos = 0);
 	
@@ -32,7 +33,7 @@ namespace CNORXZ
 	SizeT max() const;
 	IndexId<0> id() const;
 	
-	const MetaType& operator*() const;
+	const MetaT& operator*() const;
 	
 	SizeT dim() const; // = 1
 	Sptr<RangeType> range() const;
@@ -41,15 +42,15 @@ namespace CNORXZ
 	UPos stepSize(const IndexId<I>& id) const;
 
 	String stringMeta() const;
-	const MetaType& meta() const;
-	UIndex& at(const MetaType& metaPos);
+	const MetaT& meta() const;
+	UIndex& at(const MetaT& metaPos);
 
 	template <class Xpr, class F>
 	decltype(auto) ifor(const Xpr& xpr, F&& f) const;
 
     private:
 	Sptr<RangeType> mRangePtr;
-	const MetaType* mMetaPtr;
+	const MetaT* mMetaPtr;
     };
 
     template <typename MetaType>
@@ -70,7 +71,7 @@ namespace CNORXZ
     };
 
     template <typename MetaType>
-    class URange : public RangeInterface<UIndex<MetaType>,MetaType>
+    class URange : public RangeInterface<URange<MetaType>>
     {
     public:
 	typedef RangeBase RB;
diff --git a/src/include/ranges/yrange.h b/src/include/ranges/yrange.h
index c078900..94097fb 100644
--- a/src/include/ranges/yrange.h
+++ b/src/include/ranges/yrange.h
@@ -19,6 +19,7 @@ namespace CNORXZ
     public:
 	typedef IndexInterface<YIndex,DType> IB;
 	typedef YRange RangeType;
+	typedef DType MetaType;
 	
 	DEFAULT_MEMBERS(YIndex);
 	YIndex(const RangePtr& range, SizeT pos = 0);
@@ -73,7 +74,7 @@ namespace CNORXZ
 	RangePtr mRef;
     };
 
-    class YRange : public RangeInterface<YIndex,DType>
+    class YRange : public RangeInterface<YRange>
     {
     public:
 	typedef RangeBase RB;
diff --git a/src/lib/ranges/range_base.cc b/src/lib/ranges/range_base.cc
index 0084b96..b64d7b1 100644
--- a/src/lib/ranges/range_base.cc
+++ b/src/lib/ranges/range_base.cc
@@ -39,7 +39,7 @@ namespace CNORXZ
      *   RangeBase    *
      ******************/
 
-    RangePtr RangeBase::sub() const
+    RangePtr RangeBase::sub(SizeT num) const
     {
 	return nullptr;
     }
@@ -77,4 +77,14 @@ namespace CNORXZ
 
     RangeBase::RangeBase(const RangePtr& rel) : mRel(rel) {}
 
+    /****************************
+     *   Non-member functions   *
+     ****************************/
+    
+    RangePtr operator*(const RangePtr& a, const RangePtr& b)
+    {
+	assert(0); // check segfault + "flatten" yrange (no yrange of yranges etc)
+	return YRangeFactory({a,b}).create();
+    }
+
 } // end namespace CNORXZ
diff --git a/src/tests/range_unit_test.cc b/src/tests/range_unit_test.cc
index 44667f1..2fb7369 100644
--- a/src/tests/range_unit_test.cc
+++ b/src/tests/range_unit_test.cc
@@ -37,6 +37,21 @@ namespace
 
 	Vector<String> mMeta;
     };
+
+    class MR_Test : public ::testing::Test
+    {
+    protected:
+
+	MR_Test()
+	{
+	    mMeta = { "test", "strings", "foo" };
+	    std::sort(mMeta.begin(), mMeta.end(), std::less<String>());
+	    mSize = 7;
+	}
+
+	Vector<String> mMeta;
+	SizeT mSize;
+    };
     
     TEST_F(CR_Test, Basics)
     {
@@ -103,6 +118,22 @@ namespace
 	    EXPECT_EQ(x, mMeta[cnt2++]);
 	}
     }
+
+    TEST_F(MR_Test, Basics)
+    {
+	auto cr = CRangeFactory(mSize).create();
+	auto crx = std::dynamic_pointer_cast<CRange>(cr);
+	auto ur = URangeFactory<String>(mMeta).create();
+	auto urx = std::dynamic_pointer_cast<URange<String>>(ur);
+	auto mr = mrange(crx,urx);
+	auto mrx = std::dynamic_pointer_cast<MRange<CRange,URange<String>>>(mr);
+
+	EXPECT_EQ(mr->size(), mMeta.size()*mSize);
+	EXPECT_EQ(mrx->size(), mMeta.size()*mSize);
+	EXPECT_EQ(mrx->dim(), 2u);
+
+	// further tests!!!
+    }
     
     // UR_Test
     // RCast_Test