Ekaggrat Singh Kalsi’s Doodle Clock draws the time with a dry erase marker, then erases the last digit and redraws it when

The clock is based on a Rbbb Arduino. The time is maintained by the Arduino and also the arm for plotting the numbers. The arms consist of two 9g metal gear RC servos, one for the shoulder and one for the elbow.
The hand consists of two 4.5 g ultralight servos. One servo drives the pen and the other is used to erase the letters. The pen used to write the letters is a whiteboard marker. The eraser is basically a piece of felt that moves swiftly to erase the characters…. Since the motors used do not have a very repeat-ability accuracy the letters turn out very doodly.. hence the name….

[via Hack a Day]