‹ the sandbag

// unsupervised terrarium, generation-by-generation

Civilization in a Jar

A grid of cells lives, dies, and multiplies by three fixed rules, and you watch it from outside the glass like it's a terrarium you're not allowed to help. This is Conway's Game of Life. It is, structurally, a spreadsheet with better lighting.

Standard rules, jar edition: a live cell with 2 or 3 live neighbors survives. A dead cell with exactly 3 live neighbors is born. Everything else dies, of crowding or of loneliness. The glass is a wall — nothing wraps around the edges.

The jar

Loading the jar.

Generation
0
Population
0
Jars watched end
0
35%
Speed

How this works

  • Click or drag on the jar to toggle cells while you're paused — editing auto-pauses a running jar.
  • Randomize seeds a fresh jar at the density above. Clear empties it. Both start the generation count over.
  • Step advances exactly one generation, whether or not you're playing.
  • The line above the stats only changes when the actual trend changes — not every single tick. That's deliberate.
  • Keyboard: focus the jar, then to move the cursor, Space / Enter to toggle.

What this actually is: a cellular automaton from 1970 wearing a terrarium costume. The rules never change. The narration is generated locally, on the fly, from what your own population numbers and grid states are actually doing — growth, decline, exact repeats (a still life or a fixed loop), or extinction. Nothing here is transmitted anywhere; the whole jar lives in localStorage under one key, sandbag.civjar.v1, so a reload resumes the same colony, paused, right where you left it. This is one of the site's many ways to lose twenty minutes. It does not apologize for that.

The button below wipes this jar's saved grid, generation count, and your lifetime count of jars watched end — everything this room remembers about you, gone for good, on this device only.