Pictured above: A photo of glass door of a cafe in Queens, NY, looking from outside, into the cafe. The door has handles on the outside and inside that are identical, and could be used for pushing, or pulling. On the outside of the door is a decal with cut-out letters that say “PULL”. On the inside, directly opposite is a decal with cut-out letters that say “PUSH”. The effect when reading this is a superposition of two words: “P/P U/U L/S L/H”. Empirically, I determined that the door cannot be pushed from the outside, and cannot be pulled from the inside.
However my brain works, I involuntarily read both PULL and PUSH as equally valid, like perceiving both viewpoints of a Necker Cube in one mental model simultaneously. I can only defeat this door by interacting with it physically.