The stripes in front taken away: every ball is the same pale yellow.
Tricks of color
Confetti illusion
How many different colors of balls do you see?
One: every ball is the same pale yellow. Only the stripes in front of them are different.
Why? Thin stripes blend into what lies behind them. A ball behind red and green stripes takes on their color; the same ball behind blue and purple ones looks bluish. David Novick and Akiyoshi Kitaoka drew the first, in 2021; this is our drawing.
Picture: Drawn by Science Playground, after David Novick and… · Wikipedia(opens in a new tab)