The reason they look [like] different colors is because our brain judges the color of an object by comparing it to surrounding colors. In this case, the stripes are not continuous as they appear at first glance. The orange stripes don’t go through the "blue" spiral, and the magenta ones don’t go through the "green" one.
NEATOSHOP SUMMER SALE: SAVE UP TO 20% OFF ALL T-SHIRTS
Save big on Funny T-shirts, Science T-shirts, Sci-fi T-shirts & more! Ends 7/12/15