Join the Dots

Our view of the world captured on the retina of each eye is upside-down. Why, then, don't we see two separate upside-down images? Because the brain is hard at work stitching together one cohesive image. Working on a crossed-wire system, the left half of the brain is only interested in visual input from the right side of the world and vice versa. Any doubts or visual gaps, the brain fills them in, first drawing the borders and then 'coloring' in the surface area.