These devices share their name with the Smale-Williams strange attractor, which is formed by an iterated map on the solid torus. In fluidic control systems, these devices name and toggle a type of valve that can be either “normally open” or “normally closed.” The vector potential of one of these devices only has a theta component. These devices name the rotational component of a Helmholtz decomposition, which is a vector field with zero (*) divergence. A toroid is a circular one of these devices used to confine plasmas (-5[1])in tokamaks. Ampere’s law can be used to show that the magnetic field in one of these devices (10[1])is “mu-naught I N,” where N is the number of turns per unit length. For 10 points, name these coils of wire commonly used as inductors. ■END■ (0[2])