The Tetractys as a pyramid gives rise to the idea of four suits in a deck. The separation of the capstone from the base gives rise to the idea of unity being separate from the manifestations of the material world below.

There is no 5 in this Tetractys Mandala! The 5 has been replaced with an optical illusion known as Neckar's Cube. Stare at the cube, and try to decide which way it faces. Is the face on the left defining the front of the cube, or the back of the cube? Keep looking and you will notice it change back and forth endlessly. Thus it is a perfect representation for the endless unresolvable back and forth alternation of a 5, being the midpoint of a number line, or the center of a mandala.