The two-dimensional form of a hillslope when measured down the steepest gradient. Traditionally it has been divided into a number of units, each of which reflected a distinctive geomorphological process. For example, in 1957 L. C. King identified four elements in his ideal profile: a crest (or ‘waxing slope’ or ‘convex slope’) dominated by creep; then a scarp (or ‘free face’) affected by rill activity and mass movement; followed by a debris (or ‘constant’) slope where talus accumulated; and succeeded finally by a pediment (or ‘waning slope’) modified by sheetwash. Subsequently, a nine-unit model has gained some acceptance.