Each firefly keeps its own clock and flashes when that clock completes a cycle. When it flashes, it gives every firefly within sight a small nudge toward its rhythm — the Kuramoto model of coupled oscillators, published in 1975. Real fireflies of the species Pteroptyx malaccae do exactly this in Southeast Asian mangrove trees, thousands of insects syncing with no leader and no shared clock. The bar above shows the order parameter r: near 0 means every phase is scattered, near 1 means the meadow flashes as one.