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.
The Seal of Mercury follows the convention of overlapping every number of the magic square of Mercury. In addition, the seal's construction reflects the method of the square's construction, and the method is similar to the that used in the seal of Jupiter.
There are a variety of number pairings which were originally inverted in the creation of the magic square, and these numbers are all touched by the two large diagonals or the four smaller diagonals which make up the inner box. The four circles include the remaining numbers which were not moved during the construction of the magic square.