The two skeleton pictures which look like purple and orange are actually both 'red'

Despite the illustration of the dumplings that should actually be drawn in a red one, a strange phenomenon occurs when you overlay a stripe of a certain color on top of it, it looks like a completely different purple and orange. This is due to a kind of optical illusion called " Munker illusion ".

These are the skulls look purple and orange. They are both red. | Popular Science
https://www.popsci.com/red-skulls-look-purple-and-orange

The following illustration will be the subject. It looks like purple and orange rugos are written on the other side of the dark blue and yellow stripes, but in fact both are drawn in the same red color .

When you expand a part, it looks like this. The left bowl is in a state where a navy stripe is on top of a red rug, while the right rhinoceros are in a state where a yellow stripe is on a red rug.

Although it is a relatively easy-to-understand illustration that it is red when looking up, if you look at it a little away you will only see it as a purple and orange colorful trickle. This is thought to be due to the human brain characteristic "color anabolism" that averages the color of a certain part with the surrounding color, and among the illusion of the eye " illusion " related to the white effect Has become.

White effect is one of the illusion "Munker illusion". Even at the site of Professor Kitaoka Aka of Ritsumeikan University famous for illusionary images, you can see the illusion caused by Munker illusion.

Munker illusion
http://www.psy.ritsumei.ac.jp/~akitaoka/Munker.html