Part of his Protractor Series, fluorescent color saturates the interplay of as-if infinite interlocking geometrical figures (squares, circles, half circles, and quarter circles) in  Frank Stella, Harran II ( 1967). The squares and quarter circles in the center seem to lie on top of the circle even as the whole maintains a regular flatness. Eight right angles interrupt the bulls eye at the center. The composition as a whole is simultaneously hot and cool. Harran II was at the recently closed big Stella retrospective at the Whitney. I think I’m done here. These old brain ticklers are super smart and nice to look at.