Use the left and right arrow keys to rotate the screen. It's quite glitchy at the moment.
So, I was trying yet again at making a Mode 7 engine. I'm using weak perspective projection again, and it's working fine, probably because the points only vary in 2 dimensions, not 3. Update: I added in @DadOfMrLog's offscreen pen engine. It works very well, and also simplifies my code for the quadrilateral drawing block. There's still a lot to do before it's ready to use: 1. Fix the rotation glitch! I'm sure it's not the screen boundaries, because I implemented @DadOfMrLog's incredible offscreen pen drawing and the glitch still remains. 2. Fill the parallelograms. I tried using someone else's quadrilateral filler, and it didn't really work...although if I can figure out the line equations, I might be able to make this work... 3. Fill the parallelograms with a certain color. This should be easy to do. 4. Allow the user to move forward and backward instead of just rotating. Again, this should be easy to do; I can simply translate before the rotation so the translation will be affected by the rotation as well. 5. Allow the thing to read from a list. Right now, I have to hardcode the map. 6. Add sprite support. If I want to make a Mario Kart-like game, I'll need sprites for racers, trees, pipes, etc., and they'll need to move in a 3D fashion. 7. Release the full version, probably on my main account (@redyoshi857).