Orbital evolution of two black holes of masses 10⁶ M_⊙ with an initial separation of 0.819 au integrated for half a day for three integrations, pure Newton expansion, Newton with expansions to first order, and the full first-order Einstein-Infeld-Hoffmann equations. The first two are precisely on top of each other, and we plotted the first-order pairwise solution last. The last two solutions are identical because the cross-terms do not lead to deviations from the first-order expansions. The post-Newton orbits are not closed, as in the Newtonian case (green). No separate scaling of v/c is applied here because the system is initialized in physical units.