A runnable selection guide

Choose an oscillator by period

A period is the number of generations needed to return to the same phase at the same position. Start with period 2, then compare 3, 15 and 30. This collection helps you choose a pattern to run; the linked guide explains why it repeats.

Compare the runnable seeds

Period Sort by

6 patterns

Population and dimensions describe the displayed seed phase. They can change during the cycle.
Pattern	Period	Seed cells	Seed box	Experiment
Blinker	2	3	3 x 3	Run and measure
Toad	2	6	4 x 2	Run and measure
Beacon	2	8	4 x 4	Run and measure
Pulsar	3	48	13 x 13	Run and measure
Pentadecathlon	15	12	3 x 10	Run and measure
Queen bee shuttle	30	20	22 x 7	Run and measure

Start with a question

First two-step experiment

Three cells are enough to inspect every neighbour count by hand.

Run Blinker

Three visibly different phases

Step through the large symmetric pattern and compare generation 0 with generation 3.

Run Pulsar

A longer cycle

Count fifteen steps before deciding whether the initial phase has returned.

Run Pentadecathlon

How to check the comparison

Reset the seed, step through one complete period, and compare both shape and position. Keep the reaction away from the edge: the teaching board is finite, while catalogue periods describe an unbounded plane.

Read the explanation · Check the LifeWiki definition · Try the classroom worksheet