Motion trail

Full motion specification

How the movement works

Use it to show speed or a path: flying objects, cursors, points of light.

1. 01A ball (coral, radius 25, white centre radius 11) traces a figure eight once per 4.7 s: x = 196·sin(a), y = 62·sin(2a), with a advancing at constant speed.
2. 0215 copies, each placed 0.105 rad (about 0.079 s) further back along the path.
3. 03Copy radius goes 22→6 and opacity is 0.9 × (1 − i/15) + 0.05, so older copies are smaller and fainter.
4. 04Copy colour runs coral → yellow → blue from newest to oldest.
5. 05Draw the oldest copy first and the ball itself last.