In reference to what Logan and I were babbling about in class last night, the following links explain further what Siftables are and how they work. David does a slightly better job explaining them than we did. Additionally, there's a link for Hiroshi Ishii's MIT profile page, if anyone wanted further reading.
Siftables Research Page: http://web.media.mit.edu/~dmerrill/siftables.html
Siftables Video (about halfway in): http://admissions.media.mit.edu/admissions/lab-life/video/david-merrill
Hiroshi Ishii: http://web.media.mit.edu/~ishii/