In the Western occult tradition, each planet can be represented by a seal or diagram. The seal is based off of the planet's magic square, with the seal theoretically touching every number within the square, although in practice that is not always apparently the case.
As drawn here, the seal actually does intersect with every box of the magic square of the Moon. However. as commonly drawn, there are actually several squares that are not included.
Like the seals of Mars and Venus, the seal of the Moon is based off a magic square with an odd number of boxes per row. Also like those two seals, this seal commonly does not include all boxes.
However, the seals of Mars and Venus are asymmetrical, and while they bear many similarities with each other, they bear far fewer visual similarities with the seal of the Moon.
It may be more helpful to compare the seal of the Moon with that of the Sun, as Sun and Moon are commonly seen as a pair as the great luminaries of the sky. Both seals are comprised of two large, intersecting diagonals, and both contain four crescent shapes. The crescent shape is particularly appropriate for the Moon, which frequently appears as a crescent in the night sky. The common astrological symbol for the Moon is also a crescent.
Donald Tyson suggests that the 13 small circles in this seal may correspond to the 13 lunar months that are in a year. However, since he considers those circles to have only aesthetic value in the other seals, this may very well be coincidence.