Ray casting engine for the Arduino, or any AVR microcontroller.
The ray-casting engine paints to a buffer in RAM and uses the KS0108 library to send it to the LCD to paint each frame. In order to get it to run at a playable speed, the ray casting function is only called for 1/4 of the columns rendered, and the data to display the columns correctly is interpolated. The engine checks if it can do interpolation without it looking terrible (around a corner, edge of wall, etc.), and if this test fails it will cast extra rays.