Last fall, we built an oversized Digi-Comp II for MIT, which we’ll be posting about in the near future. Today, MIT computer science professor Scott Aaronson published a short “paperlet” about the computational capabilities of the Digi-Comp II on his blog, Shtetl-Optimized:

…it’s amazing that such a simple contraption of balls and toggles could already take us over the threshold of universality.  Universality would immediately explain why the Digi-Comp is capable of multiplication, division, sorting, and so on.  If, on the other hand, we don’t have universality, that too is extremely interesting—for we’d then face the challenge of explaining how the Digi-Comp can do so many things without being universal.