 Oresme’s main contributions to mathematics are contained in his Questiones super geometriam Euclidis and his Tractatus de configurationibus qualitatum et motuum. In these works Oresme conceived of the idea of using rectangular coordinates (latitudo and longitudo) and the resulting geometric figures (configurationes) to distinguish between uniform and nonuniform distributions of various quantities, such as the change of velocity in relation to time or the distribution of the intensities of a quality in relation to the extension of the subject. In the discussion of motions the base line (longitudo) is the time, while the perpendiculars raised on the base line (latitudines) represent the velocity from instant to instant in the motion. Thus uniform acceleration is represented by a right triangle. Oresme even extended his definition to include three-dimensional figures (Clagett 1974, 226–228). Thus, he helped lay the foundation that later led to the discovery of analytic geometry by René Descartes (1596–1650).