How to make a Lego compass

New Scientist : A compass that doesn’t need a magnetic needle? That might sound impossible, but the ancient Chinese worked out how to make one 4500 years ago. An ingenious combination of gears and wheels ensures that a “pointing chariot” features a needle that always points in the same direction. New Scientist includes a how-to video and links to a step-by-step guide , parts list , and kit .