Announcement: I now have a flickr account for my origami photos!  Now the images are bigger, and you can find them all in one place.  There are also lots of photos that I haven’t (yet) posted on my blogs.

Arrow Illusion, version 2. An original design.  My hand is in the photo to show that this is a real mirror.

Over a year ago, I designed an origami arrow that points in the opposite direction when looked at in a mirror.  I wanted to revisit the design, and make it easier to fold, because this is basically the most popular origami thing I have ever done.  Below, I show detailed diagrams, and a sneak peek behind the curtain.

This model was based on a paper by Kokichi Sugihara, explaining a particular optical illusion.  You can watch an amazing video showing a cylinder that has a square reflection.  My model is optimized for viewing at a 45 degree angle, and it works best at a distance (because of field of view effects).

You are free to print out these instructions.  But if you plan on distributing copies, please ask permission.  E-mail me at skepticsplay at gmail dot com, so I can give you a proper pdf.

What does the illusion look like from a different angle?  The illusion breaks down fairly quickly, as you can see here:

The red arrow on the left is not an illusion, it’s just a regular arrow I folded on the fly.