How/why do binaural beats work?

Damn, that would be good fun, although moire patterns might be easier.

Coming from the graphics industry, I’m very familiar with moire patterns. I’m wondering if there might be a way to reproduce the phenomenon within the eye/brain system, rather than outside it.

Back to the double slit experiment, if each pupil acted as a “slit”, what wavelength and distance might a light source need to be to try and replicate the interference patter within the brain? Assuming this hasn’t already been attempted before, of course.