Metaballs v4 — Contours
The same field contoured at several geometrically spaced thresholds: nested iso-lines ring the drifting balls like a topographic map of their pull.
Run marching squares at several thresholds of the same field to get nested iso-lines — a topographic map of the metaballs. Fill the bands with a palette (painted outer→inner so each level overpaints the last) and/or stroke the contour lines on top. Levels are spaced geometrically because the field grows fast near the centres.
