An LED-cube is little more than a simple set-up of LEDs connected to a microprocessor, but arranged in such a way as to give individual control of each LED, creating a three dimensional display.
The cubes come in many different variations, with mono-chromatic LEDs (above), or multi-colored (below), usually in the range of 3x3x3 – 8x8x8
The applications of LED-cubes are often limited to purely aesthetic ones and they serve little practical purpose, but are an interesting hack for exploring 3D display alternatives. They are well documented and fairly easy and inexpensive to make and are therefore popular with amateur builders and hackers.
Makezine (PDF, same as video above)
– John Adolfsson, Group E