Wheeler's delayed choice experiment

Wheeler's delayed choice experiment is an example of a strange thing called quantum weirdness. In this experiment, a particle of light (called a photon) is shot towards two options: one is one option, and one is another. Then at the last moment, we choose which option to use. Even though this choice happens after the photon is already gone, it changes the way the photon behaves! It turns out that if we choose the first option, the photon behaves like a wave, and if we choose the second option, the photon behaves like a particle. This shows us that the particle and the wave are actually the same thing!