here is a drawing which I haven't done!
some times ago Tony Burhouse send me a pencil asking me to complete it with ink, that's what I've done & after centuries I sent it back to him. Then he added some computer effects and here it is :
Check Tony Burhouse's blog : http://disorientatethedemons.blogspot.fr/ (change 'fr' to whatever)
I'm not in use with that kind of collaboration, even if I did a lot onto walls or linen etc, I'm not easy yet to manage formal collaboration. But it's interesting, I'm awaiting now to see inked the ugly pencil I sent to Tony!