Using a programming toolkit called Processing
Peter Blaškovič has created a collection of little interactive toys
based on novel interpretations of basic physics, like particle interactions. One of the newest ones, Flame
allows on to simulate, quite well the sort of long exposure work that Julien Breton (previously referenced) does in reality.
Sadly the image export function is broken on the Macintosh, but I was able to capture a sample of my work via screenshot and borrowed a sample of Peter's work from the gallery