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Iteration

Repeating a rule and watching what happens next.

Iteration means taking an output and feeding it back into the same rule. It is the engine behind many patterns, simulations and fractals.

Tiny example

Repeat a rule

Start with 2. Multiply by 2 and add 1 each time.

2 -> 5 -> 11 -> 23 -> 47. The rule is simple, but the behaviour grows quickly.

Why it matters

Once a rule is repeated, small choices can become large patterns. This is why iteration belongs to fractals, sequences, simulations and feedback systems.

Things to watch for

  • Changing the rule halfway through without noticing.
  • Looking only at the final value instead of the path taken.
  • Assuming a repeated rule must always settle into a simple pattern.

Try it in a tool