3D Life

Explore a binary cellular automaton on a 16 × 16 × 16 grid. Each cell has 26 neighbors; opposite boundaries wrap around. This is an educational finite model, not a physical simulation.

B lists neighbor counts that create a live cell; S lists counts that keep one alive. Counts must be separated by commas: B5/S4,5 is Carter Bays’ Life 4555, B6/S5,6,7 is Life 5766. The previous B4,5/S4,5 variant remains available. Every generation reads the entire previous state before updating any cell.

Generate creates generation zero. Step advances once and pauses. Start, Pause and Resume preserve the current state. A state with no changes stops automatically; oscillators do not. Random density and seed control reproducible starts. Cluster and Empty ignore these settings. Changing a rule or initial-state setting clears the old result.

Drag the 3D view to rotate; zoom with Ctrl/Meta + wheel. The fixed box represents the full grid. Select z = 0…15 to see a layer. Click a layer cell, or enter x/y and use Toggle cell, to edit it; editing pauses the animation and keeps the generation counter. Layer coordinates begin at the top-left: x increases rightward, y downward. Both views update together. Animation pauses when the tool is hidden.

Each step examines 4096 × 26 neighbors; memory is proportional to the grid size. A reproducible seed specifies an initial condition, not a guaranteed glider. Carter Bays: Further Notes on the Game of Three-Dimensional Life.

Inputs, edited grid and generation are saved locally and restored paused. Generate replaces the grid with the chosen initial state. Very large drafts keep the previous saved copy and show a warning. The layer editor remains usable without WebGL; Retry 3D rebuilds only the view and preserves the cells.