Fig. 4. Illustration of (a) the matrix used to model the distribution of particles splashed from a rectangular area (the meaning of the areas labelled SCREEN and CORNER is explained in the text); (b) a soil tray bordered by a very wide collecting screen having the same length; (c) a soil tray bordered by an infinitely large horizontal collecting screen; and (d) a soil tray bordered by a collector with vertical splash guards on three sides.