Hidden Pictures
Explanation: Here’s what happens in the experiment: the yellow bird and the red tissue paper are both reflecting light to your eyes. The red is not a pure color, but has some yellow in it. This yellow blends in with the yellow from the bird drawing, and your eyes are not sensitive enough to separate them.
Animals that are coloured similar to their surroundings are often camouflaged, or hidden, from their predators. The predator’s eyes cannot distinguish the colors well enough to separate its meal from the leaves.