Points, Walls, and Loops in Resonant Oscillatory Media

In an experimental investigation of oscillatory media, domains and walls are formed under parametric forcing with a frequency double the natural one. In this bistable system, a nonequilibrium transition from an Ising wall to a Bloch wall consistent with prediction is confirmed. The Bloch wall moves in the direction determined by its chirality with a constant speed. A new type of moving structure in two dimensions, a traveling loop consisting of two walls and N\'eel points, is observed.