Every neuron is +1 or −1. The weights are Hebbian, wij = (1/N)·Σ ξiξj, over four stored shapes (a 0-sphere, a ring, a cross and a lattice). One neuron at a time takes the sign of its local field, and nothing else happens.
Tap the grid to scratch it and watch it heal. The memory in gold is the one it is falling into. The same ?seed= always gives the same run.
LITHopfield (1982). The weights must stay symmetric and the energy E = −½Σ wijsisj must never rise between checks, or the page throws.
AMBERThe shapes are the site’s symbols; four memories is well under the network’s capacity of about 0.14N.