Well from Pop art of the 1950s you can only go one place, but Op art of the 1960s. I have art one look at some really fun op art images from Bridget Riley and a few others like that. We then talk about how to create them and to even try to create your own. I tell them from the get go that I will give them more points for attempting one of their own then copying something they found off of the internet.
I was really impressed with what I got. I have them put it into a cubed pattern with 6 different sides. I usually ask them to try to make one pattern circular, one squarish, one with triangles/diamonds, and one with just lines. That gives them two more to just play with. I know that usually these overlap but it gives them a place to start.
Sorry, I don't remember who these belong to.