Help me alter random drawing lines open source script

I found this really cool script, here:
http://levitated.net/daily/levCityLines.html
There are actually allot of cool ones on this site.

I’ve figured out how to limit it to only 4 lines, make it not fade out or move itself to center.

What I need help with is being able to specify the coordinates of the starting point of each line and the ending point of each line. I am totally a newbie, but would really appreciate any help in getting this modified . . .

Thanks!