The Japanese rock garden, or simply zen garden, has become a popular desk toy, but the folks over at Makr Toolbox have taken it to the next level with an Arduino system that lets you draw in the sand at the press of a button. The system works with a gantry that sits below the sandbox. Powered by a pair of motors, the gantry works much like those on a 3D printer, something the creator of this project has experiance with, but without the Z axis. In the middle of the gantry there is a magnet that moves a ball bearing across the sand. An Arduino Uno handles the logic and a joystick is used to control the drawing.