This week's Excel Optical Illusion is called Breathing Square
Notice the blue square, spinning in the background. To most observers it looks as if it is pulsating in size, breathing if you will. I can assure you that this is an illusion - the blue square remains a constant size at all times.
The attached workbook has a check box that toggles the masking yellow squares transparent, revealing the truth. There's also a check box governing the animation.
Regarding this illusion, the following excerpt is from Michael's site:
Usually, we are remarkably adept at detecting and identifying surface boundaries despite incomplete optical information. However, in "breathing illusions", rigidly rotating surfaces appear to pulsate or deform, even though a straightforward process of geometrical interpolation across space would reconstruct the veridical surface boundary. It is generally believed that such nonrigid outcome depends on a failure to apply a rigidity constraint across spatiotemporal discontinuities (more: Bruno 2001).
Sorry for being a day late on this illusion - minor emergency dealt with.
The workbook is an .xls and so should work in all versions.
Here it is:
Here's a list of other animated charts on Excel Hero:
If you liked this article, please share it!