See attached pic.
Update: Now fully working!
Getting ~8 fps using just one cog on 80 MHz P123.
But, speed can be dramatically improved.
Features background, textured walls and textured floor.
Try it out! Download the attached binary to your P123 and then use the left 2 buttons to turn left or right and the third button from the left to go forward. (Note: the button on the right is the reset button).