A curve of order n is generally determined by points. So a conic section determined by five points and a cubic curve should require nine. But the Maclaurin-Bézout theorem says that two curves of degree n intersect in points, so two cubics intersect in nine points. This means that points do not always uniquely determine a single curve of order n. The paradox was publicized by Stirling, and explained by Plücker.