Draw a periodic path; the solver finds the sphere whose rolling trace closes after two periods, then carves the solid that rolls your line.
Or draw your own, left to right. Ghosts show the neighbouring periods.
Solving…
Closure error (log scale) across turns per period, for the chosen closure period — longer periods wrap the trace more times before it bites its own tail. Each dot is a radius where the trace closes; click one to carve that body instead.