What Pittsburgh Zoo has managed to accomplish with their logo is a favorite trick of psychologists. You might have heard about the Rorschach test, which is performed by showing someone a series of ink blots and asking them to describe what they can see in the ink. Pittsburgh Zoo has used the principle behind those tests to design a logo which at first appears to be a tree - until you shift your perspective and begin to concentrate on the spaces, and not the ink.
When we do that, we find that instead of seeing a tree, we're looking at a lion and a gorilla coming face to face. That's a lot more exciting than a plain old tree, and we're sure we're not the only ones who've suddenly found ourselves considering a trip to the zoo in the near future. Despite the seeming aggression in the stare-down, though, we're happy to confirm that the zoo doesn't organize fights between big cats and primates!