Back in 2013 Turnvater Janosch created this ingenious and curiously mesmerizing mechanical clock that uses steel balls to show the time. Each minute a ball is released on a track—three levels of traps denote time in minute, five-minute, and hour increments. The clock is driven by a 5.5-pound weight and runs for 12 hours at a time. According to Janosch, it has an accuracy error of less than a second per day. He’s posted some stereoscopic photos of the clock in this gallery.
photo by Turnvater Janosch