Cosmograms

A cosmogram is a flat geometric figure depicting a cosmology. Some of them were created for meditational purpose. Mandalas are the best known cosmograms, but similar diagrams, known as schema, were also used in western Europe during the Middle Ages.
Many cosmograms feature a circle and a square, or a circle and a cross. The circle may represent the universe, or unity. The square or cross may represent the Earth, the four directions. The centre may represent the individual. Many diagrams featuring circles and squares or crosses may be interpreted as cosmograms, although they may not be intentionally created as such.

Here's a link to a page all about Kongo Cosmograms with some interesting info.

...One of the major functions of the cosmogram of Kongo, to validate a space on which to stand a person or charm, remains in force in certain Afro-Cuban religious circles.[see the section of the "Ken Brown Interview" when he speculates that Levi Jordan imported slaves from Cuba].Kongo-Cuban priests have said "All spirits seat themselves on the center of the sign as the source of firmness" (52). Songs (mambos) are chanted, as in Kongo, to persuade this concentration of power upon the designated point. Kongo-Cuban priests activated old, important charms by singing-and-drawing a sacred point. They chanted sacred texts in Spanish and creolized Ki-Kongo while lowering a charm from the ceiling of a shrine to a chalked sign drawn upon the floor....