An attempt to reinvent..the cube?
Sorry, this file hasn't had much effort put into it yet :/ A video to hold you over for now.
Schematic available in PDF and Eagle formats in the `schematic' directory
Since I only had enough hardware to create a 4x4x4 cube, I wanted the display to be as robust as possible. I opted to use the TLC5940 16-channel constant-current LED driver from Texas Instruments, which provides 16 independent 12-bit PWM channels, each of which can sink >100mA of current. My goal was to be able to use a single 16-channel driver to drive all 192 channels by using a multiplexing scheme. To acheive this, I grouped the LEDs into individual "pages" of 4 LEDs. The LEDs within a "page" share a common anode; cathodes are shared among LEDs in corresponding positions within other pages.
The design of the cube allows for only a single "page" of LEDs to be driven at any given moment. The 16 pages which make up the cube are driven in sequence at about 100Hz (full-cycle period).