Builder 1

From Softology's collection · B4,6,8-9/S2,6,9/C10

Sparse builders sprawl through the box, trailing eight generations of dying cells.

How the rule works

Each cell has 26 neighbours: every cell that shares a face, an edge or a corner with it (the Moore neighbourhood).
An empty cell comes alive when 4, 6, 8 or 9 of its neighbours are alive.
A live cell stays alive when 2, 6 or 9 of its neighbours are alive; otherwise it starts dying: for 8 generations it fades, is not counted as a neighbour and blocks births, then the cell is empty again.
With 10 states in all (alive, 8 dying, dead), this is a Generations rule.

It starts from a random block in the middle of the box, 50% full and a third as wide as the box. Each run uses a new seed.

B lists the neighbour counts at which an empty cell is born, S those at which a live cell survives, and C the number of states. How to read a rule