cardium
A living sheet of excitable tissue wrapped on a sphere that composes itself over minutes — from a calm heartbeat, through a spiral rotor, into fibrillation, and back.
Design notes
FitzHugh–Nagumo (Barkley reduction) excitable medium on a geodesic icosphere. Per vertex: excitation + recovery, diffusively coupled along mesh edges. An internal clock slowly varies refractoriness so waves self-organise: calm → rotor → fibrillation → self-termination, then re-seed. Listening regions convert passing wavefronts into a rhythmic pulse whose tempo tracks the local wave period. See the folder README for full mechanism and references (FitzHugh 1961; Nagumo 1962; Barkley 1991; reentry & spiral waves — Winfree).