Ink

Draw in the air. Your hands are the pens and your face is the palette.

pinch — ink flows  ·  release — travel
fist — erase  ·  smile — the ink warms
open mouth — the ink pours

Camera, face, hands, drawing — all stay on this device. Nothing is uploaded, ever.

This needs WebGPU — current Chrome, Edge, Safari, or Firefox on most machines.