[PD] a crunchy noisy unpitched kind of affair

[nward04 at qub.ac.uk]

Hi, Im being a bit lazy here but thought I'd ask in case anyone had a start 
on this. I need a patch to generate some sound. It will be controlled by 
just one potentiometer's position and velocity and must generate unpitched 
sound. So i guess I'll use the velocity to control amplitude and the 
position will control some other element related to timbre, or something. I 
was thinking of something like a sound of a sweeping brush or gravel being 
raked. Any quick patches or approaches to get me started would be great. 
thanks in advance Nicky