Which of the lines on the right, is the continuation of the black line on the left?
red one
blue one
none of them
both of them
This is known as Poggendorff illusion, first described in 1860. Many detailed studies of the illusion point to its principal cause: acute angles in the figure are seen by viewers as expanded.
globalquiz.org
reach: rather globalillusionsoptical illusionstechnology
Answers by country
red one
blue one
none of them
both of them
answers

23

15

356

160

18

16

300

133

21

14085

153

57

22

28

13

141

21

20

26

14