[portreathbeach] built this simple 3x3x3 LED matrix. It uses a PIC16F690 in a ZIF socket for the brains. Each layer has nine LEDs with the cathodes tied together. The anodes from each LED are connected to the LED below. The LEDs are multiplexed so that even though all layers appear to be on, they’re being addressed individually. He’s included software, so you can build your own animations. Video of the matrix in motion is after the break.