This is not meant to be snarky, but what's the point of this? What use does the pattern being uniquely generated from a SHA of a distinct string have over a random pattern being generated from a SHA of some random string?
Say I'm using this to generate a background image for each post on HN. Also, I want them to be consistent, so everywhere you see a mVChr post it's got a green ringed background.
I could generate a random string for each user, but then I'd have to store it somewhere. It's better to just use the username as the seed.
It's the same fundamental principle behind identicons.
