(a–c) Development of spatial patterns in the field. (a,b) A mussel bed at 2 months and 4 months after larval settlement in May/June 2009, on a tidal flat in the Wadden Sea (near De Cocksdorp, The Netherlands). (c) A mature, undisturbed mussel bed in the Menai strait (near Bangor, United Kingdom). (d–f) Model predictions of the development of self-organized spatial patterns at two spatial scales, nested within one another, in mussel beds of 4, 40 and 400 days old. The insets show a magnified view of the nested patterns.