Eventually, reproduce a blank square of the same size as the initial square, rotate it 45 degrees, and center it on the larger square pattern (Fig. C), creating a blank diamond-shaped space. Then, connect the black lines that intersect the edges of the diamond as illustrated in Fig. D.
As you can see above, the pattern in the central diamond appears to slightly shift or float above the contrasting background when you move your eyes around while viewing the figure. Scrolling the image horizontally or vertically can create an even stronger effect.
When adding a deep blue color to the pattern while leaving the thick rhomboidal frame black produce a peculiar effect: an illusory yellow shade emerges from the black lines!
However, when a yellow background is added to the pattern and the interior of the thick rhomboidal frame is left blank, another illusionary effect occurs: the frame takes on a blueish appearance.
We can play endlessly with these patterns; here is an interesting variation…
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