Made as a teaching aid for understanding distributions, this is an acrylic photograph holder (two slabs held together with magnets) milled on a CNC mill to provide channels through which small ball-bearings can fall. The milling was done with a V-shaped bit on the inner surface, which closes up to a triangular channel. At each stage, the ball-bearing can turn left or right with equal probability, and as expected, the majority land near the middle, with extreme positions very unlikely.
See http://en.wikipedia.org/wiki/Bean_machine
Just a bit of fun.
oilulio 