Time Twister 3
Time Twister 3 is a digital clock built out of LEGO bricks.
Each digit is made up of three vertical sections with black and white tiles arranged in particular patterns. Each section can rotate 360 degrees before it hooks to the next section. By twisting the outermost section back and forth in a specific sequence, you can arrange the sections so that the desired digit is displayed.
Each section clicks in place using a lever pulled by a rubber band.
The clock uses two motors. One for the hour digits and one for the minute digits.