Posts: 22
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Joined: Feb 2011
Very cool. I haven't seen these before.
Posts: 653
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Joined: Aug 2010
All this - especially the well known property of moving colored shapes making algebra wrong ;-) - works because our eyes simply do not work sufficiently accurate to distinguish two very similar, yet different slopes in the red/green and blue/orange shapes (first example) resp. the red and green triangles in the second example.
If you look more closely you'll notice that the slopes of the mentioned shapes are slightly different, so they cannot be arranged the way the final layout suggests. One the one hand it's 3:8 boxes, on the other hand it's 2:5. In other words: 0,375 vs. 0,4. Which is so close that the difference it is not obvious for the human eye.
Dieter
Posts: 2,761
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Joined: Jul 2005
This picture might disprove the equality:
Another interesting illusion:
http://alexbellos.com/?p=742