Metatron’s Cube is a symbol that’s meant to represent the journey of energy throughout the universe, and of balance within the universe. It is made up of all the Platonic Solids, but it also has thirteen circles in it to represent the thirteen archangels (with Metatron’s circle at the center). All of the circles are connected by straight lines, as well, which represents the feminine and masculine as intimately tied together, showing that everything in the universe is connected to everything else. If you tug on one string, then that can reverberate through everything, like a Butterfly Effect sort of energy.
The Cube is also a representation of how energy flows throughout the universe. While the point of origin may be the tree of life that Metatron guards (or the throne of god, depending on your interpretation), the energy moves through him, and through the other archangels, out to the furthest point of all creation.