In this science the illustrations and examples are not confined in their effect merely to the practice they afford in the analytical art, but [...] they also store the mind with independent geometrical and physical knowledge. Besides, it should be considered, that the only effectual method of impressing abstract formulae and rules upon the memory, and, indeed, of making them fully and clearly apprehended by the understanding, is by examples of their practical application.
Dionysius Lardner (1823). A System of Algebraic Geometry. G. and W.B Whittaker. p. vii-viii.