How to use it
Pick a source, press Stream, and watch dots pile onto the screen one at a time. Each is a single particle; the striped pattern only emerges from thousands. Then raise the which-path detector and watch the stripes flatten into two plain bands.
What you're actually seeing
The lower panel is the detection screen: every particle is one glowing dot, deposited where the wave P(y) says it may land. The thin curve is that probability. The top strip is a not-to-scale cartoon of source → two slits → screen.
Wave–particle duality
With both slits open the particle's wave passes through both and interferes with itself, so dots avoid the dark fringes. Learn which slit it took and the wave collapses: V² + D² = 1. You can have the stripes or the path, never both fully.
What's exact, what's stylised
Exact: the far-field intensity, the de Broglie wavelengths, the complementarity bound. Stylised: the apparatus cartoon, the human-scaled slit sizes, and how fast the dots accumulate. The verdict — interference is real, looking erases it — is never softened.