I'm just a layman with an interest in science, so my terminology won't be accurate. Sorry. Set up for question: the wave-front splits as it passes through the slits and must (I guess?) condense to a point upon impact with the recording device (paper/film etc). The question: if a photon is given to behave as a wave until it contacts matter, and thereupon condenses to a particle, why doesn't the wave condense when part of it strikes the barrier through which the slits are cut? Also, if you cut slits in the recording paper is the process repeated through a second iteration (albeit at a diminished intensity)? Thinking about this experiment is driving me insane. A logical explanation seems always just out of reach. Thanks in advance for any light you can shed on this for me.