Illusion Of Giving An Illusion

(I am taking an art class, and one of our assignments is to create a graphic that uses some kind of color illusion. I create mine, and submit it to the class’s digital submission board with the added note, ‘It might look like that rectangle in the middle changes color, but it doesn’t! The gradient effect is the illusion. Feel free to download this and test it with your eyedropper tool!’ Many of my classmates commented on how they had tested it for themselves, how interesting the illusion was, etc. Then…)

Teacher: “This is not an illusion! I said you had to create the ILLUSION that colors were changing!”

Me: “But it IS an illusion. That rectangle doesn’t actually change color, it only looks like it does. It tricks your eyes into seeing a color change when there isn’t one.”

Teacher: “It’s not an illusion. Redo it!”

(I don’t know what she thought the word ‘illusion’ meant, but she was adamant that my submission was not one, and I had to redo the whole assignment.)