Tetris (dungeon tiles 2)

The first thing to do with the Dungeon tile idea was to start working out what shape the tiles were going to be. Using my tried and tested methods, I figured I would start drawing out little sections of corridor until I got bored, or I had enough ideas to fill my 12 slots. However, as I was drawing them I realised they looked like Tetris pieces, and I noticed that there were only so many shapes you could make with so many squares (I'm sharp like that). So after playing Tetris for like and hour, I started working out what you can do with a set number of squares,
1. - you cant do much with, 2. -nothing here either (there's rules here I'm taking for granted, like each square has to connect up along a side), but when you get to 3. things start to get interesting (I use interesting in it's loosest form, it was interesting to me) and with 4. and 5. things get quite complicated (...). So I sketched out all the variations I could think of for sets of 1,2,3, 4 and 5 squares. Which looked like this.
There were 25 of them (I didn't think of the 'dead end' until near the end) and that was above my budget of 12 tiles. I was starting to think I would only go up to the 4 set when I remembered that some of the combinations were the mirror of each other, so all I would have to do was point out that the tiles could be printed 'mirrored' and you would get the rest of the combinations. And so that let me pretty much pick all the interesting combinations and a few varying lengths of straight corridor. While I was doing that I was thinking about the whole maze thing and thought I needed a dead end in there as well, so I made the executive decision to increase the budget to 13 (since I'm the art director on this, it was pretty easy to wangle, which is not normally the case). Apt that the dead end is 13 eh?
So my Dungeon tile set now looks like this