Download spirograph.xls

This is an Excel spreadsheet that will generate the curve drawn by a Spirograph kit, once you have specified the dimensions of the wheel etc that you are using. No macros are used.

Troubleshooting

The Maths

The locus of the tip of a pen fixed to a wheel rotating in the hole from from a Spirograph set is called a Hypotrochoid. I generate it with the following steps: