Perhaps another way to look at this is with the image below ...
Here, the first circle (top left), albeit it is a representation of height versus width (two dimensions), can also be used to project the four dimensions of time and space -- "spherically" that is. Hence where all four points come together, in the center of the circle as well as the sphere, we have "perception" (5). Which, is the whole point ... if we don't perceive (5), we don't understand.
And, since our perception comes from heaven above (5), and we are grounded to the earth below (6), a synchronicity exists between heaven and earth. ESP or, the "6th sense" anyone? Hence the marriage (7) of Heaven (5) and earth (6) ... (567).