WHAT DOES IT MEAN?

It's reasonable to feel like this results of this experiment are spooky. There are ideas proposed as to why we get different results when observing, but most of them are a bit super-natural. This experiment can even suggest that light and quantum particles have some kind of consciousness to them, but at this point there's no way to prove anything of the sort. As far as producing multiple interference patterns, light is both a wave and a particle, a property that nothing else in the natural world has. The dynamics of light are one of the most facinating things in the universe, and this experiment really shows that off.