[pstricks] Marble, Granite Fill Styles

[Christopher Ellison]

I'd like to generate backgrounds (psframes) that have some random texture to 
them.  An example would be the "popcorn" texture on many household walls.  
Other examples of textures are stone-like fill styles---such as marble and 
granite.

Ideally, I would like this to be "randomly" generated with each use.  That 
is, if I include a two frames in a document,  I want the second pattern to 
be differ slightly from the first.

Is there any way to do this?