Abstract painting style popular in the 1960s (2,3)

I believe the answer is:

op art

(Other definitions for op art that I've seen before include "modern movement" , "Created illusions" , "Style of abstract painting using illusion etc" , "Nineteen sixties illusory painting style" , "Illusory visual form" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.