This flat graphic symbol represents the cosmos and is often used as a meditative focus. The mandala is a cosmogram, as are the elaborate depictions of tortoises holding the planet. Cosmogram commonly features the most basic shapes of the circle that represents the planet and unity. The square on the symbol is the earth and the directions.
Nozedar Adele, The element encyclopaedia of secret signs and symbols, 2008, Cosmogram, p 62