The Pixel Roller is a very interesting project, and as of now it comes in two forms. The first version uses phosphorescent ink that leaves trails of light upon a screen.
The pixel roller does exactly what it say it is, rolls pixels. It can be viewed like a hand printer, the pixel roller can roll out any image, video or text manually, at any speed or direction, round corners and over surfaces.
In the first prototype, 'Light Roller', the pixels are in the form of a series of 12 ultra bright UV LEDs situated along its axis. These UV LEDs excite phosphorescent ink and leave trails of pixels that fade with time.
The second version uses a mechanical roller and paint which is hooked up to a computer. As the painter uses the Pixel Roller the computer figures out which part of the roller is printing where, in otherwords it's like a hand printer except it's usable on any surface and at any scale.
For videos of the Pixel Roller, check out these links:
Pixel Roller Prototype 1
Pixel Roller Prototype 2
Link (via Wooster Collective)