Steiner Chain

Mutually-tangent circles filling the annulus between an outer and inner circle, regular (concentric) or offset (inner circle off-center; the inner radius is solved so the chain still closes).

Input

Output Static SVG Rotating GIF/MP4

Circles Offset (moves the inner circle)

Theta0 (deg) Offset angle (deg) Outer radius

Outer circle

Fill Stroke Stroke width

Inner circle

Fill Stroke Stroke width

Chain circles

Fill Stroke Stroke width

Animation

Theta0 above is the starting angle; the chain rotates by "Cycles" full turns of its own n-fold rotational period over "Frames" frames.

Frames Cycles FPS

Size (px) Format Loop count (GIF, 0=infinite)

Circles capped at 40 and frames at 90 for animations, to keep renders quick.