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 additionally used in western Europe throughout the Middle Ages.
Many cosmograms feature a circle and a square, or a circle and a cross. The circle might represent the universe, or unity. The square or cross might represent the Earth, the four directions. The centre might represent the individual. Many diagrams featuring circles and squares or crosses might be interpreted as cosmograms, although they might not be intentionally created as such. For example, traditional Chinese coins that are round with a square hole in the middle, have been given such an interpretation, and so has the board for the game ludo, see Cross and Circle game.