How is this polygon called? (the one over the circles)

square
rhomboid
concave square
concave rhomboid
In this Ehren­stein illusion the sides of a square placed inside a pattern of con­cen­tric circles take an apparent curved shape. But in reality, the sides are straight.

Answers distribution

square
rhomboid
concave square
concave rhomboid
answers
flagFinland
95%
0%
0%
5%
20
flagSpain
86%
0%
11%
2%
36
flagNorway
78%
9%
9%
1%
52
flagCroatia
75%
10%
5%
0%
20
flagPoland
74%
10%
8%
5%
17781
flagthe Netherlands
71%
9%
17%
1%
52
flagthe United States
70%
9%
10%
6%
936
flagthe United Kingdom
70%
8%
12%
6%
483
flagGermany
70%
9%
9%
8%
235
flagRepublic of Ireland
69%
6%
10%
10%
65
flagFrance
69%
10%
9%
9%
55
flagItaly
69%
19%
9%
2%
42
flagDenmark
69%
7%
19%
3%
26
flagCanada
67%
13%
13%
3%
58
flagAustralia
66%
11%
7%
13%
51
flagBelgium
66%
12%
12%
4%
24
flagSweden
65%
20%
10%
5%
20
flagthe United Arab Emirates
60%
20%
10%
10%
20
flagIndia
57%
10%
15%
13%
215
flagthe Philippines
46%
9%
18%
25%
32

Gender

men76%
women76%
square
76%
76%
rhomboid
10%
11%
concave square
8%
7%
concave rhomboid
5%
5%

Language versions

question
answers
results
flag
How is this polygon called? (the one over the circles)
1795
66%

Details

Author: Debbie Fox
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