Which lines are parallel?

blue and red only
green and red only
green, blue and red
none
This is a well known Zöllner il­lu­sion, first de­scribed in 1860. It may be caused by this im­pres­sion of depth. The black lines are par­al­lel, too!

Answers distribution

blue and red only
green and red only
green, blue and red
none
answers
flagCroatia
0%
6%
86%
6%
15
flagSpain
5%
10%
80%
0%
20
flagAustralia
0%
4%
79%
15%
44
flagthe United Arab Emirates
15%
10%
70%
5%
20
flagPoland
4%
9%
69%
15%
10094
flagthe United Kingdom
4%
8%
69%
15%
316
flagFrance
0%
7%
68%
18%
38
flagItaly
3%
14%
67%
14%
28
flagNorway
5%
15%
65%
15%
20
flagthe United States
5%
7%
64%
20%
745
flagGermany
4%
15%
64%
15%
137
flagUU
5%
5%
64%
23%
17
flagIndonesia
0%
0%
64%
35%
14
flagthe Philippines
4%
4%
60%
28%
25
flagthe Netherlands
11%
5%
58%
22%
36
flagIndia
6%
10%
54%
23%
194
flagCanada
5%
11%
54%
24%
53
flagRepublic of Ireland
5%
11%
50%
33%
36
flagDenmark
21%
7%
50%
21%
14
flagSouth Africa
0%
31%
43%
18%
16

Gender

men67%
women72%
blue and red only
5%
4%
green and red only
10%
7%
green, blue and red
67%
72%
none
16%
14%

Language versions

question
answers
results
flag
Which lines are parallel?
1496
63%

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.