Stonehenge robot clock arm tells time by arranging little cards

The Stonehenge Robotic Clock from Norris Labs is a robot arm that tells time by plucking numbered cards from an array around its body, setting them down in front of itself, waiting, then doing it again with fresh cards. Depending on the time-change, it can take more than a minute to advance by one minute -- the robot knows this, so it skips those minutes and jumps straight to the next one, timing its motions to finish the advance right on the dot.

Stonehenge - A Robotic Digital Clock

(via Make)