An example of something that joubert is referring to is the fact that photoreceptors (rods and cones) in the human eye are actually located behind the retinal g

An example of something that joubert is referring to is the fact that photoreceptors (rods and cones) in the human eye are actually located behind the retinal ganglial cells, nerve fibers, and capillaries. So light has to pass through a layer of tissue before being detected. One consequence of this is the blind spot. An engineer would probably try a different ordering.