[Mpark’s] propeller controlled Etch-a-Sketch is well built and very accurate. He was inspired by the Step-a-Sketch project and he’s carried that design through to a stunning conclusion.

This is the approach [Carl Bugeja] took with his Spherical Folding Propeller design which he has entered into the Open Hardware Design Challenge category of The 2018 Hackaday Prize. While at rest ...