It shows, with diagrams, how a object above us, drop down to eye level, once it approaches the horizon, or the vanishing point, due to the rules of perspective.
Because once we view a object at a small enough angel, we will not see it anymore. The higher you get, the further away the horizon will appear, as the angel we view a far distance object increases.
Yandex image search for perspective diagram:
https://yandex.com/images/search?text=perspective%20diagram&from=tabbar
It shows, with diagrams, how a object above us, drop down to eye level, once it approaches the horizon, or the vanishing point, due to the rules of perspective.
Because once we view a object at a small enough angel, we will not see it anymore. The higher you get, the further away the horizon will appear, as the angel we view a far distance object increases.