In addition, hair parameters like length, curl, and clumping are modified every time, so that each sheep receives its individual "hair style".
As a next step, the algorithm needs to pick one or more "props" - hats, glasses, shoes:
A random number is mapped via a curve. If the curve is exponential, it makes it more likely for objects higher up in the hierarchy to appear. A curve that flattens in the middle would favor the objects in the middle of the hierarchy. The scene is set up so that more complex objects (full masks or a baby sheep) are much less likely to be picked than the average baseball cap.