In the above example, the contacts produce a standard binary count as the disc rotates.

As the disc rotates, it grinds against surrounding ice -- smoothing into a circle.

If the load supplies power to the grid, the disc rotates backwards unless prevented by a ratchet, thus making net metering possible.

As the aircraft's angle of attack increases and the propeller disc rotates toward the horizontal, the airflow will meet the propeller disc at an increasing angle.