The grid is a world of squares. Each square is either alive (glowing) or dead (dark). Every generation, all squares look at their 8 neighbors, the squares touching them on the sides and corners, and change at the same moment by three rules.
The three rules
SurvivalA live square with 2 or 3 live neighbors stays alive.
LonelinessWith 0 or 1 live neighbors, a live square dies.
CrowdingWith 4 or more live neighbors, a live square dies.
BirthA dead square with exactly 3 live neighbors comes to life.
The outlined square in each picture is the one being decided. The grid wraps around: a square on the right edge counts the left edge as its neighbor, so patterns that drift off one side come back on the other.
Controls
- Play / Pause runs the world. Step moves forward one generation. The space bar also plays and pauses, and S or → steps.
- Speed sets how many generations run each second, from 1 to 60.
- Tap or drag on the grid to draw live squares. Start a drag on a live square to erase instead.
- Add a pattern places a famous shape in the middle of the grid.
- Random fills about a quarter of the squares. Clear empties the grid and pauses.
- Grid − / + changes how many squares fit across (16 to 120). Your pattern stays centered.
- Gen counts generations since the last Random or Clear. Alive counts live squares.
- Color shows age: new squares glow mint green and turn blue the longer they survive.
The patterns
- Glider
- Five squares that walk diagonally across the grid forever.
- Spaceship
- A slightly bigger traveler that moves straight sideways.
- Glider gun
- A machine that fires a new glider every 30 generations.
- Pulsar
- A large symmetric shape that flashes through 3 forms and repeats.
- Pentadecathlon
- A bar that cycles through 15 shapes before repeating.
- R-pentomino
- Just 5 squares, but it churns for over a thousand generations before settling.
- Acorn
- 7 squares that grow into a sprawling colony with several gliders.
- Diehard
- Busy for exactly 130 generations, then disappears completely (on a big enough grid).
Things to try
- Draw a straight line of 3 squares: it becomes a blinker, flipping between flat and upright.
- Draw a 2 × 2 square: a block never changes.
- Fire the glider gun on a small grid and watch the gliders wrap around and crash into it.
Invented by mathematician John Conway in 1970.