Last August, Marc wrote about Albert Hwang’s Wiremap display. It’s a 3D display technology which uses a standard projector to illuminate an array of vertical strings. The strings are carefully spaced so that a vertical row of pixels on the projector can illuminate a single string. This allows objects to be rendered in a three dimensional physical space and as you can see from the video, it’s pretty amazing to look at.
The whole project is released under the Creative Commons license. Even better, Albert recently posted an Instructable which guides you through the finer details of making one yourself from scratch. Aside from the projector, the cost is fairly negligible, and it would be an easy way to go about producing your own three dimensional artwork.