In ancient Greece, astronomy was a branch of mathematics; astronomers sought to create geometrical models that could imitate the appearances of celestial motions.

It explained geometrical models of the planets based on combinations of circles, which could be used to predict the motions of celestial objects.

In a later book, the Planetary Hypotheses, Ptolemy explained how to transform his geometrical models into three-dimensional spheres or partial spheres.

In mathematics, a bundle gerbe is a geometrical model of certain 1-gerbes with connection, or equivalently of a 2-class in Deligne cohomology.

Spock erected geometrical models in his mind.

But I wanted to find a simple, geometrical model underlying that uncertainty.

Such geometrical models make it possible to extract additional information (including numbers of crystals).

Somehow he had access to Babylonian observations or predictions, and used them to create better geometrical models.

The Greeks however preferred to think in geometrical models of the sky.

Plato taught about 'astronomia' and stipulated that planetary phenomena should be described by a geometrical model.