A pyramid is a cube upon which rest four triangular sides.
Symbolically, a cube is identical to a square; it is the number four, the number that corresponds to matter and to the four elements.
A cube represents everything that is solidly established in matter, everything that is built to last. However, the cube is just the base of a pyramid, and this base supports four triangles.
Compared to a square, which is the symbol of matter, a triangle is the symbol of the spirit, three being the number of the divine principles – light, heat and life. Four (matter) plus three (the spirit) equals seven, the number of man.
The head is three; the two arms and two legs four; and the three is placed above the four. So, three joins with four to form a living being: seven.