Another new demo of the crater illusion has been produced! Columns (a) appear to be convex whereas columns (b) to be concave, though the luminance gradient of the former is just the mirror image of that of the latter.pic.twitter.com/HNmFEmpqat
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Contrast polarities of line segments are not essential. Columns (a) appear to be convex whereas columns (b) to be concave, though the luminance gradient of the former is just the mirror image of that of the latter.pic.twitter.com/tpJbWDBtD6
It seems that the reversal is occasionally observed, too.
Yeah, for me the two alternate.
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