Time Twister 4
Time Twister 4 is a digital clock built entirely out of LEGO bricks.
The clock display is made up of a matrix of cubes that can be pushed out to show the time.
Each digit is powered with a motor that drives a conveyor belt with small knobs arranged in patterns that affects a mechanism that pushes or retracts the cubes.(The 10-hour digit is simpler since it only needs to show the digit 1 or no digit at all)
Movement: Two LEGO Mindstorms NXT Intelligent Bricks. Five Servo Motors.
Width: 82 cm (32 inches)
Height: 36 cm (14 inches)
Weight: 8 kg (18 lb)