Fan Circuit.

Fan Circuit is a 3D circuit board that behaves like the real thing. Two AA cells in series feed a small brushed fan motor through a three-position slide switch: OFF, LOW and HIGH. In HIGH the motor is wired straight across the 3 V pack. In LOW the current goes through a 22 ohm resistor first, so the motor sees about a third of the voltage and turns slower. A red indicator LED sits across the motor and only lights when the motor terminals rise above its forward voltage, which in practice means HIGH.

Nothing about it is animated by a timer. The motor is simulated as a real DC motor with armature resistance, a back-EMF constant, bearing drag and air drag, stepped many times per frame. Switch it on and the current spikes to about 500 mA while the rotor is still, then falls as the fan spins up and its back-EMF builds. Settled, HIGH draws about 290 mA at roughly 600 RPM and LOW about 87 mA at roughly 264 RPM. Switch it off and the rotor coasts down on drag alone. The panel shows the supply, the voltage across the motor, the current, the power and the shaft speed, and says in words which path the current is taking.

The board is drawn in code: the copper traces, pads, labels and silkscreen are painted on a canvas and wrapped onto the board, and the cells, switch, resistors, LED and motor are built from simple shapes. Glowing dots travel along each wire that is carrying current, faster when more current flows. Airflow particles rise from the fan with its speed. The on-screen spin is slowed down so it does not strobe, and the readings stay true to the real speed.