Famous Optical Illusions

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Answer this question in the quiz to reveal the explanation.

Question 1

Which famous illusion created in 1889 shows two lines of equal length appearing different due to inward or outward arrows?

Question 2

What classic ambiguous figure created by Danish psychologist Edgar Rubin in 1915 flips between two profiles and an object?

Question 3

In the Ponzo illusion (1911), why does the upper horizontal bar appear longer than the identical lower bar?

Question 4

Which wireframe wire cube first published by a Swiss crystallographer in 1832 shifts between two depth orientations?

Question 5

What illusory visual contour was demonstrated by Gaetano Kanizsa in 1955 using three pacman-like shapes?

Question 6

Which room illusion designed by an American ophthalmologist in 1946 makes people appear to shrink or grow as they walk across it?

Question 7

Which optical illusion demonstrates an impossible object created by Lionel Penrose and his son Roger Penrose in 1958?

Question 8

What neural mechanism explains the Hermann grid illusion where ghostly gray smudges appear at line intersections?

Question 9

Which motion illusion demonstrated in rotating spirals leaves stationary objects appearing to expand after viewing?

Question 10

What phenomenon occurs when viewing a bistable spinning silhouette dancer, where viewers see it rotating clockwise or counterclockwise?

Which famous illusion created in 1889 shows two lines of equal length appearing different due to inward or outward arrows?