The mechanic

A tide is the sum of eight cosines at fixed astronomical periods; the set-piece assembles that sum one constituent at a time, resynthesising at every step rather than tweening between baked paths. Springs and neaps are not drawn — they are the M2/S2 beat at 14.765 days.

The control case. /ports/brindley-dock/ — a dock impounded above a sill: all eight amplitudes 0.000 m, drawn spread 0.0000 px.