Threedifferent interior perturbers in red that can produce the same eccentric belt (thick black) from an initially circular belt. Orbits that deviate from the belt will be sheared by differential precession, as exemplified by orbits of older halo particles (lighter blue) trailing that of freshly produced ones (darker blue). The location of the star is marked by grey cross hairs. The perturber’s periapsis is indicated by red lines.