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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blue and red only
green and red only
green, blue and red
none
answers
flagCroatia
0%
4%
92%
4%
25
flagSpain
4%
8%
75%
8%
24
flagAustralia
1%
7%
73%
17%
57
flagSwitzerland
0%
7%
73%
19%
26
flagthe United Arab Emirates
12%
6%
72%
6%
33
flagSweden
5%
2%
71%
20%
35
flagPoland
4%
8%
70%
16%
19633
flagthe United Kingdom
4%
8%
69%
15%
478
flagFrance
0%
7%
68%
19%
63
flagUnknown
2%
8%
67%
20%
1405
flagNorway
3%
16%
64%
16%
31
flagDenmark
16%
8%
64%
12%
25
flagthe United States
5%
8%
63%
20%
880
flagGermany
5%
12%
63%
17%
235
flagthe Netherlands
8%
6%
63%
19%
73
flagItaly
7%
13%
60%
18%
38
flagCanada
5%
10%
58%
22%
67
flagRepublic of Ireland
6%
8%
57%
27%
47
flagthe Philippines
7%
7%
55%
25%
40
flagIndia
6%
11%
54%
22%
248