 A couple points are worth emphasizing. First, Descartes presents the more complex curves generated by his compass as described by motions that can be as “conceived as clearly and distinctly” as the motions required to construct the more simple circle. And because of the clear and distinct motions needed for their construction, these curves are legitimately geometrical. That is, consistent with Descartes’ general criterion for constructing geometrical curves, these complex curves can be used in the solution of geometric problems. Second, we see that although Descartes takes care to distinguish the concerns of geometry from those of mechanics, he does not steer away from the construction of curves by means of instruments. Although instrumental constructions are mechanical constructions, they can nonetheless give rise to geometrical curves precisely because the motions of the instruments are “clearly and distinctly” conceived. That the motions are generated by instruments does not render the resultant curve non-geometrical. (For more on the use of instruments in La Géométrie, see Bos 1981.)