I was actually thinking about it, but wasn't quite sure about the best way to add one. What level are you stuck on? (also is it the demo or full version since the level names are different)
3-16A of the full game (I know it has to be the V shaped piece since I solved 16B but still can't solve it)
Ah, I noticed one or two other people have also gotten stuck on that level.
The level is a little scene with a house.
Place the shared V tile pointing up in the center, with a one tile gap from the top edge.