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
9%
0%
81%
9%
11
flagthe Netherlands
6%
0%
80%
13%
15
flagPakistan
0%
20%
80%
0%
10
flagGreece
7%
0%
76%
15%
13
flagGermany
8%
8%
72%
11%
62
flagMalaysia
0%
7%
71%
21%
14
flagthe United Arab Emirates
14%
0%
71%
7%
14
flagUnknown
7%
7%
70%
14%
27
flagAustralia
4%
6%
68%
20%
45
flagPoland
4%
8%
67%
18%
18125
flagthe United Kingdom
3%
10%
65%
19%
166
flagthe United States
5%
8%
60%
23%
659
flagIndia
8%
12%
50%
25%
224
flagthe Philippines
8%
8%
50%
27%
36
flagCanada
4%
12%
48%
34%
49
flagSouth Africa
7%
30%
46%
7%
13