In the second, horizontal dimension we can distinguish characteristic varieties corresponding to the degrees of a differential relation within a given order, and to the distribution of singular points for each degree (such as the equation for conic sections which gives according to the case an ellipse, a hyperbola, a parabola or a straight line; or the varieties of animal ordered from the point of view of unity of composition; or the varieties of language ordered from the point of view of their phonological system).