# Excel Optical Illusions Week #28

This week’s Excel Optical Illusion is called The Mutually Interfering Shapes Illusion and was originally created by Maarten Wijntjes, Robert Volcic and Tomas Knapen. The illusion was a 2008 Finalist in the Best Illusion of the Year Contest hosted by the Vision Sciences Society.
Here is how they described the illusion for the contest…

A circle’s a circle and a square’s a square, right? Wrong! Just look at the center of our MISillusion display and you’ll see why – Two dots are moving around bouncing off one another. Do you see a square and a circle? They really are! The illusion becomes even stronger when tracing the inner square closely: you’ll see the outer dot moving along four arcs instead of one circle. If you now follow the outer dot, the square suddenly seems curved inward!
So watch out next time you track a baseball pitch, your brain might just throw you a curveball!
My Excel version of this illusion is much smoother than the animated GIF above can reproduce. Wow that’s starting to sound like a broken record, but it’s the truth.
This is an XY Scatter chart with a little VBA for the animation. I’m very happy how it turned out, especially the color fading happening simultaneously with the rest of the animation. Again, the workbook is much, much better than the GIF.
Here is the file.
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Why do I share these optical illusions? The techniques that are used to make them, when mastered, can be used in many other Excel projects, in charting, formula crafting, and formatting. Learn them. They will aid you on your journey to become an Excel Hero.
Here is a list of other Excel Optical Illusions here at Excel Hero:
And here’s a list of other animated charts on Excel Hero:
– Excel, A Presentation Platform (Number Spiral)
– Lilac Chaser (Optical Illusion)
– Stereokinetic (Optical Illusion)
– Illusory Contours (Optical Illusion)
– Breathing Square (Optical Illusion)
– Enigma (Optical Illusion)
– Two Sinusoids (Optical Illusion)
– Perpetual Collisions (Optical Illusion)
– Freezing Rotation (Optical Illusion)
– Reverse Spoke Illusion (Optical Illusion)
– Stepping Feet Radial Illusion (Optical Illusion)
– Swimming Fish (Optical Illusion)

– Mutually Interfering Shapes (Optical Illusion)