Left: example of chaotic transformation of a nonhierarchical system of four single stars into a temporary 2+2 quadruple (black/red + blue/green), which subsequently breaks up into a binary (black/red) and two single stars (blue and green). Right: example of a nonhierarchical configuration of two primordial binaries (2 and 3) that bind to form a stable 2+2 quadruple system, as an interloper flies by and carries away the excess energy. The formation of a quadruple system is far simpler when the binaries have formed prior to their interaction. Both simulations show the dynamical interactions of point sources without any gas.