We use a simple, collision-based, discrete, random abrasion model to compute
the profiles for the stoss faces in a bedrock abrasion process. The model is
the discrete equivalent of the generalized version of a classical, collision
based model of abrasion. Three control parameters (which describe the average
size of the colliding objects, the expected direction of the impacts and the
average volume removed from the body due to one collision) are sufficient for
realistic predictions. Our computations show the robust emergence of steady
state shapes, both the geometry and the time evolution of which shows good
quantitative agreement with laboratory experiments.Comment: 9 pages, 6 figure
