Plugins: Spirograph

Spirograph is an old toy that reproduce a special set of mathematical curves called hypotrochoids and epitrochoids. More on this on Wikipedia.
This plugin only needs few inputs:

• External Radius
• Internal Radius
• Offset Radius
• Target Depth

Different from real plastic toy, you can even try negative radius. Hard to immagine but fun to try.
All values are expressed in the units you are using(mm/inch)
Once data are imputed, you can hit the execute button. Then it'll reproduce a completed curve, self calculating the required numbers of spins to complete the modulo of the path.

Stock material defined in the material database will provide the used Work Feed, Plunge Feed, Safety Z height and Depth Increment.
If Target Depth can't be reach by End Mill in one pass, it'll create more passes.

Enjoy!