Grids are constructed to draw in palpable energies from the world of potentials - in other words, to increase your Luck, your Cosmic Attraction.  The images in the grids are the focus - what you want to attract.  The sacred geometry is the 'motor' of the grid - typically that's a Flower of Life.  The stones & objects that come with the grids are the 'gasoline', they provide power.  More about the Flower of Life:  Geometry is found everywhere in the Natural World.  Number and shape are the language of the Universe.  FOL has actively been in use by alchemists and those who understand cosmic mystery since Egyptian times.