Corn Gear is a gear-design exercise. The teeth of the gears are wound in a helix around a cylinder at a 13:5 angle. Two mirror-image corn gears can roll over each other at 0 degrees, like normal gears, but at 90 degrees as well. The corn gears can also roll over a flat gear bed. See also https://www.shapeways.com/product/LHNA2EFBH/corn-gears