Spirograph

Draws a hypotrochoid: the geometric curve you get from rolling one circle inside another with a pen offset from the center. The N/D ratio between the outer and inner radii sets how the loops nest. Think of it as the digital version of the toy.

Inputs

Port	Type	Default	Range	Description
Size	Scalar	1.0	0–1	Overall scale
N	Scalar	5	2–12	Outer radius. Controls the bounding shape
D	Scalar	1	1–8	Inner radius. Controls how tightly the curve loops

Outputs

Port	Type	Description
Frame	Frame	Closed spirograph curve

Ideas

Set N=5, D=3 for a classic five-loop star. N=7, D=4 produces a tighter weave with more crossings.
Animate D with a slow Phasor so the curve continually morphs between forms.
Feed into Colorize with Hue driven by Phasor for a constantly shifting hypnotic pattern.

Tips

The curve closes after loops = D / gcd(N, D) revolutions. Coprime N and D give the longest, most intricate curves.
N=D is invalid (the inner circle equals the outer). The node clamps D to stay below N.

Rosette: petal-and-weave variation
Rose: simpler rhodonea curve
Spiral: open inward-to-outward path