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|Number of cells||21|
|Year of discovery||2017|
Runny nose is a period-3 oscillator found by ConwayLife forums user "83bismuth38" on 5 March 2017. It is notable due to its small size, at 21 cells, which surprised many due to it not being found earlier, and as such it fills in gaps in oscillator collections.
- 21P3.111 at Heinrich Koenig's Game of Life Object Catalogs