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.

Answers distribution

red one
blue one
none of them
both of them
answers
flagthe United Arab Emirates
79%
3%
13%
3%
29
flagSpain
72%
5%
11%
11%
18
flagthe Netherlands
66%
22%
5%
5%
53
flagCroatia
64%
11%
5%
17%
17
flagSwitzerland
63%
10%
15%
10%
19
flagGermany
59%
19%
12%
9%
141
flagCanada
53%
17%
17%
7%
28
flagItaly
52%
19%
25%
2%
36
flagNorway
52%
9%
14%
23%
21
flagthe United States
51%
18%
18%
11%
405
flagthe United Kingdom
48%
18%
20%
12%
280
flagIndia
47%
25%
17%
8%
123
flagPoland
45%
20%
19%
13%
11154
flagthe Philippines
45%
20%
15%
20%
20
flagRepublic of Ireland
42%
15%
25%
17%
40
flagFrance
40%
37%
15%
6%
32
flagSweden
40%
35%
20%
5%
20
flagRussia
40%
30%
20%
5%
20
flagAustralia
38%
19%
30%
11%
26
flagUnknown
34%
18%
29%
17%
803

Gender

men43%
women45%
red one
43%
45%
blue one
16%
22%
none of them
23%
18%
both of them
16%
13%

Details

Author: globalquiz.org
Illustration: globalquiz.org
tools
Should this question be improved? Improve it.
Globalquiz questions are translated by users for other users. Translate this question.