Sacred Geometry refers to forms and patterns that exist in nature and are therefore the building stones of all that exists on earth. The patterns can be found everywhere - in the movement of the stars, the regular ebb and flow of the tides, etc. The Egyptians, Mayans and Celts, to name but a few, built their ancient monuments according to this sacred geometry.
Our Universe is based on solid geometric values, of which the Golden Ratio (1.618) is the most important. Two quantities are considered "in the golden ratio" if the ratio between the sum of those quantities and the larger one is the same as the ratio between the larger one and the smaller. In nature, the Golden Ratio is found everywhere; plants, flowers, shells, snow flakes, crystals, butterflies and dolphins are marked by this ratio. Human beings are also affected by the Golden Ratio. The proportions of our face, heart beat and DNA are based on this ratio.
Also important are the 5 Platonic Bodies, named after Plato; the Tetrahedron, Cube, Octahedron, Icosahedron and Dodecahedron are unique forms that are found in our Universe and possess certain defining attributes:
Although these bodies were eventually named using the nomenclature that Plato proposed, they have existed from the very beginnings of our universe - perhaps time itself. Some believe that Plato learned the Sacred Geometry from Pythagoras and he, himself, explains that much of his information was found under the Pyramids in Egypt. 
Archaeologists have found these forms carved into stone which dates back 20 000 years. Their existence in our universe is omnipresent and yet no one really knows where they come from.
Metatron's cube: wherein the five forms and their movements are present.
The code of the Flower of Life contains the wisdom of the Universe in exactly the same manner as our genetic code is locked within our own DNA.
Source: The ancient secret of the Flower of Life, volume 1 by Drunvalo Melchizedek.