Spirograph is a geometric drawing device.  It produces mathematical curves known as hypotrochoids and epitrochoids. As a child I loved drawing with my Spirograph set, it thoroughly fascinated me. The limitless symmetrical designs that could be created were formed mysteriously as the plastic numbered disks whirled around the page. The pen markings have been replaced by stitched threads in random and orderly patterns to mimic Spirographics.