Lava Hash

Twelve lava lamps on two shelves, a small cousin of the hundred-lamp wall in Cloudflare's lobby. The wax is a simplicial complex. The wall photographs itself and hashes the picture.

What the camera sees: the shelves, never the sign. 96 by 54 pixels, one photo every half second.
warming up
SHA-256 of the pool after the latest photo.
Photos taken0
Bytes absorbed0
Components, β₀, whole wall0
Holes, β₁, whole wall0
Topology per frame0 ms

Each lamp holds 30 beads of wax. Two beads that overlap are joined by an edge, three that all overlap fill a triangle. That is a Vietoris–Rips complex at scale ε. The bulb heats the wax at the bottom until a clump breaks off and rises, cools at the top, and sinks to be heated again.

Persistent homology follows every component and every hole across all scales. The label under each lamp is its barcode, dim bars for components, bright bars for holes, with the tick at ε. Click a lamp to heat it.

Every half second a camera photographs the wall, and the photo, the barcodes, frame timing and your mouse are stirred into a SHA-256 pool. The sign under the shelves scrolls what comes out. Toy, not a CSPRNG.