I have a fairly simple scene with two cubes and a sphere on a plane. Each of the items has an image texture applied to it and a point lamp provides illumination.
The sphere has a slightly more complex material:
Images of the scene rendered in Cycles show a very unusual artifact:
As you can see, there is a very strange "staircase" pattern in the shadow of the UV sphere. What is causing this and how can I get rid of it?