A single coral polyp seen from above: a calcareous cup with a ring of tentacles that sway in the current as travelling waves run down their length, phase-offset so the crown ripples. Drifting plankton specks are swept into reach, curl toward the mouth and wink out as the polyp feeds, the oral disc pulsing orange. Rendered in a fluorescent-coral palette — GFP green tentacles, orange glowing tips and mouth. Pointer sets the current direction, scroll sets the flow strength, press fires a feeding pulse that contracts the crown inward.