I needed something cool to encourage people to join my Circuitry Club in high school, so I built a persistence-of-vision display on a bicycle wheel.
The wheel has 90 sectors and 28 radial pixels for a total of 2520 effective pixels. Images are first resampled from standard rectangular formats to a custom radial format where each pixel is specified by its angle and radius, then loaded into the PROGMEM on an AVR microcontroller. The microcontroller simply measures rotation speed with a magnet and uses pulse-width modulation to apply 8-bit RGB color to each LED.
Get the code here.
The image appears continuous in real life, but the frame rate of the video camera interferes with that.
Yes, Pikachu's missing part of his face. I only had two days to build the thing. Cut me some slack.