diff --git a/assets/adv01/adv01.js b/assets/adv01/adv01.js
index a871a57..7fdc3f0 100644
--- a/assets/adv01/adv01.js
+++ b/assets/adv01/adv01.js
@@ -14,6 +14,8 @@
     wall.push(Crafty.e("Wall").wall(390,0,10,387));
   
     var cur_sel; // "Pointer" to current selected creature
+
+    var meters=50; // px/m, should be set such that the size of a player is ~ 0.4m x 0.4m
   
     var player={};
     /* initialize Players ("Player") and creatures ("Beast") */