pleion
The XOR Sierpinksi's triangle is at http://sciencevsmagic.net/logicgrid/#282800 but there are other ways make it too. For example XNOR makes an inverse http://sciencevsmagic.net/logicgrid/#828200
If you keep hitting random you'll find plenty of surprising analogues to Sierpinksi's.
There are lots of libraries that could have made things more convenient. But a big part of this project was to learn as much as I could about coding, and the browser as an environment, so early on I committed to writing everything myself.
I'd be interested in hearing whether or not other people think this is a good strategy for self teaching.
As for the hash, the original reason why I went with hash= was to preserve back and forward, but I guess that might not be so necessary considering I have undo and redo.
I know that my clutter can be a bit obnoxious, but just changing it to window.replace(hash) breaks a few other things, so it's left the way it is for now.
There is probably some HTML5 history API way to do it that lets me have back and forward without saving every history entry, I'll look into it.
The minimum scores are from the simplest solutions I came up with during development, I was waiting for someone to best me.
I've probably done something a stupid way somewhere and it's not working in certain cases. What browser/os are you using?
EDIT: My chrome is okay (windows 7) but I'll check out a few others. Does the cursor always come out tiny or only in place of one of the pointer/grab hand?