In extremely arid places (usually with less than seven inches of annual rainfall) a combination of extreme environmental forces may combine to form desert pavements: broad, barren areas of closely packed stony material, winnowed by the wind and abraded by sand. Cima Dome in the Mojave Desert is one example, a place where lava ﬂows of recent age, geologically speaking, partially covered by younger soil layers, developed the stony carapace of a desert pavement. In a region with more precipitation, such mosaics might be broken up regularly—or prevented from forming—by the persistent force of plant growth. In hyper-arid areas, no seeds germinate on pavements. The more they are hardened by environmental forces, the more unlikely their breakup becomes; in the rare event of rain, all water ﬂows quickly into runnels between the pavements. Viewed from the air, these pavements shine like nude, muscular interﬂuves veined with narrow bands of vegetation.