Abstract: A modular archery target comprising a plurality of hexagonal prismatic foam segments and a plurality of rhomboidal prismatic foam segments configured to form an archery target in the shape of a single hexagonal prism. Each of the hexagonal prismatic foam segments and each of the rhomboidal prismatic foam segments is replaceable, interchangeable and reversible, and each of the hexagonal prismatic foam segments is also rotatable. Each of the hexagonal prismatic foam segments and each of the rhomboidal prismatic foam segments is preferably comprised of flexible, self-healing polyurethane foam.

Abstract: Means are described for controlling the asymmetry of the leeside vortices developing over a pointed object placed at an angle of attack in a flowing fluid. Unlike prior art, the stagnation point controller biases the vortices at their point of origin. Resulting devices enable rapid and precise control of vortex asymmetry. The amplitude and rate of such motion is used to control the amplitude and rate of the asymmetry. Complex types of variations in asymmetry are demonstrated. The stagnation point controller is used in inventing means of controlling the yawing and rolling moments of aircraft and other solid objects at high angle of attack in fluid flow.