The Jastrow Illusion

BBC Academy trainer Marc Blank-Settle points out something strange about the pieces to a wooden train set: Apart, one track appears larger than the other, but placed atop each other, it is clear they are actually the same size.

The video above demonstrates what’s known as the Jastrow illusion, a tricky brain teaser that may arise from how two objects’ angles are compared.  The objects are in fact the same size, it’s just hard for our brains to see them that way.

Via