Life on the Stratasphere

Conway’s Game of Life, played on the surface of a sphere instead of a flat grid. Each generation becomes a shell. The present is outermost, and the past sinks inward toward the first generation at the center. Every newborn cell is joined to the three neighbours that gave rise to it, so the whole history hangs together as one figure.

The inner shells are not smaller. They are farther.

Drag to turn the sphere, scroll or pinch to zoom. Click a cell on the outer shell to light up everything it came from.

generation0

cells on the sphere0

alive now0

lives so far0

on a line to the present0

Run

Generations per second 6

View Density gradient 2.0 Cut away the near side Show the fur Turn slowly

World Cells along each cube edge 18 Starting density 0.30 Spontaneous births 0.2%

Spontaneous births are cells that appear with no parents, a trickle of new founders that keeps the sphere from settling into stillness. The size and density settings take effect with “New sphere.”

Why a sphere

On a flat grid the history of Life stacks into a box. On a sphere it nests, and nested spheres are what the stratasphere is: a series of infinitely nested 2-spheres… an approximation of a 3-sphere. The storyboard proposed Life as its first application because it would be rapidly recognized by the general readership of science.

Three parents, not two

In Life a dead cell comes alive when exactly three of its neighbours are alive. Those three are its parents. A cell that survives is its own continuation, drawn as a short radial line. Because every birth has three parents, the lines braid together as well as branch, which is closer to how cultures and technologies descend than to a family tree.

The grid

The sphere is a cube inflated into a ball, with each face divided into squares. Each cell counts its eight nearest cells as neighbours. At the eight corners, where three faces meet, the eighth neighbour is slightly farther away than the rest. It is a small imperfection that the flat game never has to face.