Sketch of the mechanism of eccentricity excitation due to non-axisymmetric infall of material on parabolic orbits. Following the arrows: 1. Material infalls onto the disc on an effectively very eccentric orbit. 2. This infalling material carries large AMD, so when acreted it increases the AMD in the discand excites material in the outer orbits of the disc. 3. The resulting disc has an eccentric outer disc and more circular inner disc. 4. Through AMD transport the disc settles into a long-lived configuration.