Scratch Card

a scratch card: nine symbols under a silver coating, and three of a kind wins a code. the card leans toward the pointer, lies flat under a press, and sheds shavings that blow off it when the prize comes up.

key insight: the brush is the edge of a tilted coin, an ellipse with two nicks in it, so it clears a wider band across than along and leaves streaks a second pass takes. the scratch is one looping noise whose level, pitch and pan follow the coin's speed, place and the coating under it.

a pen's pressure and a finger's contact patch scale the coin's edge, and a phone ticks under a finger on foil.