Friday, March 2, 2012

Gardner's Dragon


Martin Gardner (1914-2010) wrote mathematical games and puzzles for Scientific American magazine.  I remember trying to figure out some of those puzzels as a kid.  He also was interested in stage magic and wrote for the Skeptical Inquirer

Every other year there is a "Gathering for Gardner" held in Atlanta in memory of Martin Gardner.  On the third gathering binary arts made a memorial paper dragon based on the hollow face illusion, and inspired by Jerry Andrus' illusions.  In this illusion a face that is carved convexly (instead of concave as we expect) seems to follow your movement.  Faces work especially well for this as our mind of attenuated to detect, recognize and interpret subtle face signals.  (In fact it has been suggest that we represent complex data in the form of a face to be easier to visualize complex patterns.)  This leads us to see faces in patterns where they don't actually exist. 

Anyway, when it works this is a powerful illusion.  We saw a version of this a couple weeks ago while visiting an animation class at a charter school in Honolulu.  There is a PDF available for download to cut out and assemble one.  Yesterday, while M was at work with me she cut out and assembled a couple and gave them to my coworkers.

After viewing the video above, look at these out-of-range pictures to break the illusion.


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