There is a note on another page about it:

https://www.redblobgames.com/grids/parts/#more

> Spiral Honeycomb Mosaic [0] (search the page for "Spiral Honeycomb Mosaic") is an interesting way to assign numbers to hexagons in a hexagonal grid. It results in bizarre properties.

[0] http://paulbourke.net/geometry/tilingplane/