Escher loved doing what I've heard termed 'parquet deformations' where he altered one line in a pattern, repeated it and then altered another etc. so he came out with a very different pattern at the end of a line than he had at the beginning using incremental changes.

I have been trying to find a particular quote by Rufus Jones, about significant change being effected by small groups of people in small meetings. However I keep runnign into information about Rufus Jones the wrestler and I have to go now. I'll see if I can find it later, I used to have it written on one of my University Binders.