# cycle (loop)

drift of a parameter that returns to a previous state so the same path can occur again

- Computed level: L15 (depth in the emergence graph, not abstraction)
- Status: review  ·  Domain: window  ·  Arena: emergence

## Emergence
**Emerges from:** [drift](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-drift.aimless), [parameter](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-parameter.condition), [window](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-window.range), [wall](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-wall.range-end), [occurs](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-occurs.event), [previous](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-previous.temporal), [return](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-return.movement), [state](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-state.condition)

**Through:** repeatable drift within bounded condition change

**Novel properties:**
- periodic recurrence
- return to prior state
- bounded oscillation

## Examples
- The 11-year sunspot cycle repeatedly brings increased solar flares and geomagnetic storms on Earth. *(astronomy)*
- A thermostat switches heating on at 18°C and off at 20°C, maintaining room temperature in a continuous loop. *(engineering)*
- The Krebs cycle in mitochondria processes acetyl-CoA to produce energy, regenerating its starting molecule. *(biology)*

## Used by
- [rhythm](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-rhythm.temporal) (L16)
- [season](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-season.climate) (L16)
- [vicious cycle](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-vicious-cycle.stacked) (L16)

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-cycle.loop*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-cycle.loop.json*  
*Every definition provably resolves to space, time, energy and pattern.*