The drifting particles are a single hour of wind — whichever hour the scrubber is sitting on. Drag it, or let it run.

The colour along the shore is something different: it's the wind added up over the window you pick — 1, 3 or 7 days of it pushed into each bank, not one moment. Green through red runs lightest to heaviest. Press play and you'll watch it build from bare shore.

Build-up shades every bank on that scale, so you can see the whole lake at once. Prime banks keeps only the top 10% — the banks the wind has genuinely been stacking into, and nothing else.