I found this delightful little programme called Alchemy yesterday.
The website describes it this way:
"Alchemy is an open drawing project aimed at exploring how we can sketch, draw, and create on computers in new ways. Alchemy isn’t software for creating finished artwork, but rather a sketching environment that focuses on the absolute initial stage of the creation process. Experimental in nature, Alchemy lets you brainstorm visually to explore an expanded range of ideas and possibilities in a serendipitous way."
Even after spending a few hours playing with it I can't offer a better explanation. Not much more than its fun, it gives a way of editing the output in both vector and bitmap formats and its available for Win, MacOSX and Linux. It's a fairly advanced alpha (no crashes at all so far), and it has a lot of potential. I'm just not quite sure for what, yet....
