The pattern of "terracettes" or so-called sheep tracks is formed by soil creeping down the steep scarp slope of the chalk of the Wiltshire Downs.
Westbury White Horse, Wiltshire, England
"Steep slopes on chalk downland develop a ribbed pattern of grass covered horizontal steps a foot or two high. Although subsequently emphasised by cattle and sheep walking along them, these terracettes (commonly known as sheep tracks) were formed by the movement of soil downhill, a process known as soil creep. This still active movement probably results in alternate heating and cooling, and wetting and drying of the soil, together with the steepness of the slope and the binding action of the roots. It can be simulated by gently jogging flour down a piece of coarse sandpaper." (http://www.sevensisters.org.uk/education/chalk.html)