I have found strange glitch In general my hero is destroying boxes, if box has instance variable "coin = 1"
then it generates coin (with moveto behavior) and moves the box up (wait 0.4s) and down;
if box has instance variable "coin = 0" then just moves the box up (wait 0.4s) and down
and now the funny part: if I change instance variable value from 1 to 0 at beggining or in the middle of events list, then 2nd box movement (going down) differs with a few pixels = it gives funny view of boxes on little different levels
if I change instance variable value from 1 to 0 after all moveto movements, then everything is fine