Here’s even more open source code for creating new sound interfaces using free-moving blocks for control. We looked at Sonicforms, which is both intended as a project and a repository for information. Chris’ project uses a projector aimed at a tabletop for additional feedback, and IR lights for sensing. That adds cost to the system and makes it less portable (though it does provide a cooler visual interface.)
The d-touch project, in contrast, uses tags on the blocks that are recognized by a simple webcam (fiducial recognition). Advantage: no projector, no fancy interface, ultra-portable, ultra-cheap. Sure, you lose out on the tricky visuals (and, importantly, visual feedback) — but you get the even more mysterious effect of moving around ordinary blocks with strange hieroglyphics on them.
d-touch features cross-platform C++ code (compiled on Mac OS X, but tested on Linux and Windows, too); the code is open source and regularly updated. Give us a buzz if you do something with it, because I can’t program my way out of a paper ba– uh, tangible interface.