One gesture, one rule
Slide to follow the edge: the nozzle follows your finger, no button, no timer, no lives. Slightly inside, the cord gets messy. Slightly outside, it droops: that is the warning. Stay clearly outside and the cream falls. Splotch. A new cake starts at once, no screen in between. The cake never speeds up: only its shapes change, from circles to soft waves, scallops, hearts and rounded stars, never the same twice. Every shape is checked so that following the edge always works and standing still never does.
