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!
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Very interesting!
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Answers by country

blue and red only
green and red only
green, blue and red
none
answers
flagSingapore
8%
0%
83%
8%
12
flagAustria
0%
10%
80%
10%
20
flagSwitzerland
0%
6%
80%
13%
15
flagFrance
0%
7%
76%
15%
13
flagPakistan
0%
23%
76%
0%
13
flagMalaysia
0%
6%
73%
20%
15
flagRepublic of Ireland
9%
9%
72%
9%
11
flagthe United Arab Emirates
14%
0%
71%
7%
14
flagAustralia
2%
9%
70%
16%
71
flagUnknown
7%
7%
70%
14%
27
flagGermany
5%
8%
69%
16%
109
flagthe Netherlands
5%
5%
68%
15%
19
flagPoland
4%
8%
67%
18%
18980
flagGreece
4%
8%
65%
21%
23
flagthe United Kingdom
3%
10%
64%
19%
196
flagthe United States
5%
8%
60%
23%
720
flagIndia
9%
12%
53%
22%
265
flagthe Philippines
7%
7%
50%
28%
38
flagSouth Africa
7%
28%
50%
7%
14
flagCanada
3%
11%
49%
33%
53