Four rules on a seven-day grid

Life runs on four rules applied to every cell at once, counting its eight neighbours:

• A living cell with two or three living neighbours survives.
• A living cell with fewer than two dies (loneliness), more than three also dies (crowding).
• A dead cell with exactly three living neighbours is born.

The twist here is the shape. A contribution graph is only seven rows tall (one per weekday) but about fifty columns wide, so this is Life on a long, thin strip. To stop everything from dying against the top and bottom edges, the board is a torus: the last row wraps to the first, and the last week wraps to the first. Gliders that march off the bottom reappear at the top a column later.

The green shading is not the original commit count once things start moving. It tracks each cell's age: a newborn is the faintest green, and a cell that manages to survive several generations darkens toward GitHub's deepest green. Stable little structures (blocks, beehives) glow dark and steady, while blinkers and gliders stay pale because they never sit still long enough to age.

The seeding threshold decides which days count as alive at the start. At Seed ≥ 1 every day with any activity lights up, which on a busy graph is dense enough that the first few generations are a bloodbath of overcrowding before it settles into oscillators. Push the threshold higher and only your heaviest days survive the seeding, so the board starts sparse and most of it quietly goes extinct.

Left alone, almost every start settles within a minute into a handful of blinkers and blocks, with the odd glider tracing across the weeks before it wraps. Draw your own cells, reseed from the real graph, or push the threshold around, and watch which shapes a given year of commits happens to contain.