Evolution of the the virial ratio −2K/U (top panel), the fluctuations of the total energy δE in units of the initial energy E₀ (middle panel), and the norm of the total angular momentum δL (bottom panel) for the same isotropic Plummer initial conditions with N = 2 × 10⁴ particles, evolved with the direct N-body code (black lines), the exact angular momentum preserving MPC scheme (light blue lines), and the faster MPC rotation with a random axis (purple lines). The initial conditions have a slight angular momentum due to the randomised initialisation procedure for stellar velocities.