The puzzles are generated by code, I didn't sit down and draw out a million puzzles. A user enters sizes from 5 x 5 up to 33 x 19, odd numbers only (12 x 4 will resize to 13 x 5). Each tile has one of four states: light bulb, I-shape, L-shape or T-shape except for the four corner pieces which can only be a light bulb or L-shape. The center piece has one of three states: one door, two doors or three doors.
I'm hoping to find a formula not just an number because I'm working on rewriting this game in another program (sort of: it's currently Flash and I want to convert it to Adobe AIR). Currently the game can generate any size puzzle but I restricted it to 33 x 19 because it took too long to generate puzzles and the pieces got to small. I'm hoping the rewrite will solve this and allow larger puzzles.