Does exactly what it says it does.  Small and well formed.  IF (big if) I was to suggest any improvements I'd say 

1) ability to export drawings to PNG or whatever would be cool, as would save/load/ or some means of sharing patterns

2) not 100% on first play how to set rot speed when dropping shapes.  Also not clear how to edit or even if elements CAN be edited. 

but these would be 'nice to haves', game isn't worse off for not having them!