This paper describes a series of drawing machines made from scrap bicycles by the author. The characteristics of these machines are discussed, as are the maths and geometry of the curves that can be drawn with them. These patterns include: hypotrochoid (“Spirograph”), harmonograph (aka Lissajous curve or “pintograph”), and epitrochoid (“reverse Spirograph”). Some context is provided: science-inspired art made by the author from everyday materials, geometric drawing toys, and other artists investigating similar themes.