It seems to me that light travels (in a room) from everywhere, to everywhere else: A complicated, messy, interconnected network of photons of varying wavelengths which somehow avoid ever colliding with each other. This is what allows me to see things, and other people to see other things without our "lines of sight" ever getting in the way of each other. Add to this the fact that infared (heat) photons are also traveling through this space (from every angle, to every angle), as well as radio station signals, WiFi signals, cell phone signals, cosmic rays, cosmic microwave background photons... It seems like the number of photons in a cubic meter must be inconceivable. One auxiliary question: At what scale do we not see a complicated network of photons constantly coming in from everywhere, to everywhere, and start to see gaps? Also, why do photons seem to be able to share space and never ever collide? Do they, and we just don't see it?