# Six inch, clear plastic binary counting puzzle

About 30 years ago I remember playing with this puzzle. It was a device that was mainly a cylinder about 6 inches in diameter and perhaps 3 inches tall. The base was black plastic, and there were multiple plastic wafer discs stacked on each other to make up the height of the cylinder. There were 8 black plastic "levers" sticking out of the top. These could be slid toward the center or the edge of the cylinder, if the slots cut into the various wafers allowed. Moving the pins also caused one or more of the wafers to rotate.

The idea was to move all the black levers from the center to the edge, or vice versa. I now know the solution was basically binary counting (although at that time I simply discovered the pattern) - each of the levers represented a bit, and the value as a whole could only increment or decrement by one (only two levers could really be moved at any one time, and one was always the LSB).

Can someone provide me with information about this puzzle? I'm particularly interested in the shape of the wafer discs, but a product name would at least get me started.