Scientist 1: The bare circular patches in the arid grassland are made by termites. Colonies at the center of each disk consume the roots of any plants that sprout there, keeping the interior bare. Moisture stored in the cleared soil feeds a ring of taller grass at the margin. On this view the regular spacing of the disks reflects the spacing of hostile neighboring colonies, so the pattern should appear only where these termites live.

Scientist 2: No insects are needed. Plants compete fiercely for scarce water, and vigorous plants draw down the soil moisture around themselves. This kills the plants in the depleted patch, leaving a bare gap. The way water diffuses through the soil sets a preferred distance between gaps, producing an evenly spaced pattern purely through self-organization of the vegetation.