Observing how color behaves and how it creates optical illusions

For our next exercise I played with colored stripes. First I tried playing with shades of purple coming into tones of dark yellow. But it did not really speak to me much. Then I tried playing around with more colors but it usually ended up as a mix of colors that I didn't really like. It felt like...well to heavy and it created an illusion that the stripes move (inward).

Then I tried to play with colors similar to each other in terms of um...how to call it tone? type? This came out of it. Something I can actually look at and something that is pleasing to my eye. Unlike the previous ones.