1. Man has 2 eyes in front, while for instance a hare has them located on each side of his head in order to get a full view of his surroundings - this makes it easier for him to survive surprise attacks from a big cat trying to get him from behind.

 

The advantage of 2 eyes in front must have been considerable, because in his childhood also man had to be aware of dangerous predators. The advantage is the capacity to see in depth, to be able to estimate distances ahead. It was useful while jumping from tree to tree in the forest.

 

In ancient Egypt a right wedjat eye meant Sun and a left one meant Moon. Modern man relies heavily on his right eye, so let us therefore take a quick look at the world from the other side, to use our inherent faculty of 'perceiving in depth':

Inside (in the dark of) the great circle at top center are 2 + 1 'persons. The last of them has turned around, a sign of 'end' or 'old age'. Below this great black 'cycle' are 2 Moon crescents tightly bound together. Probably it means 2 * 29½ = 59, because it is necessary to add 2 consecutive lunar months in order to reach a countable (natural) number.

 

The Moon wedjat is riding in a kind of ship, which of course is necessary for travelling across the 'watery' domain on the 'back side' of the world.