Twisted Scroll Ring in Excitable Media (from SIADS Poster):

This image shows simulations of scroll-shaped waves often found in excitable media - such as heart tissue and chemical reactions. The scroll wave is viewed as a color isosurface of a concentration field. The surface is clipped halfway through the cubical simulation volume. The wave is organized about one-dimensional filaments shown in white. The structure is known as a twisted scroll ring, after Winfree and Strogatz, because the phase of the wave changes (twists) around the approximately circular ring. The two arrows show the 180 degree phase shift of the wave in one half turn around the ring.