Tetris on a 16×8 LED matrix display

Graham designed a portable Tetris game on a PIC18F4520. It uses two 8×8 LED matrices as a display, and 4 buttons for control:

The 64 LEDs and four buttons are controlled by a single PIC (18LF4520) and two AA batteries. The source code operates very efficiently, and the program is extremely responsive. I was worried about the latter as I was determined to use algorithm based graphic rotations as compared to predefined constants. From here I could use a similar approach to create other interactive games!