Classical vs quantum walk

Both walkers start at the center and take 80 steps. The gray one takes a classical random walk — coin flip, step, coin flip, step — and settles into the familiar bell curve. The cyan one takes a quantum walk, and does something strange: it refuses to settle in the middle and spreads to the edges instead, piling up in two sharp horns at the outer limits of where it could possibly be.

Drag decoherence. At zero, the quantum walker stays weird. Turn it up and the weirdness drains out step by step until you're back to the bell. The slider is the dial that turns quantum into classical.