Upper panel: assuming TNOs as triaxial ellipsoids, with axes a>b>c (rotating around the short axis c corresponding to the lowest energy state of rotation), we obtain two brightness maxima and two minima per rotation cycle (double-peaked light curve) as illustrated in the curve. The maxima correspond to the largest cross-section of the object projected in the direction to the observer. Lower panel: if the TNO is a MacLaurin spheroid with an albedo variation on its surface, we obtained one maximum and one minimum per rotation cycle (single-peaked light curve). Note that the ordinates are magnitudes, not brightness.