Just to tell you that the blocks themselves are not optical, just look at the throw pillows. It's when you start putting the blocks together that they start to look crazy and make you get dizzy.
I've got another optical illusion pattern I picked up on Deb Tucker's website called Abstraction as the young man asked for modern in blues, purples and whites. So I've got his fabrics all pulled from my stash already.
Jamie Wallen has a book out all about optical illusions and I finally found mine again. There's a block I want to try out someday when I have all these other quilts finished and out of here.