Streptanthus cordatus stem. Flowers occur at intervals along the upper stem. Each has a calyx of sepals roughly a centimeter long which begin greenish yellow and mature purple. Four purple petals emerge from the tip of each calyx. The fruit is a thin, narrow silique which may reach 14 centimeters in length or longer. Streptanthus cordatus Streptanthus cordatus is a species of flowering plant in the mustard family known by the common name heartleaf twistflower. It is native to the western United States, where it can be found in many types of sagebrush, woodland, and forest habitat. It is a perennial herb
Surround channels Surround channels Surround channels are audio channels in surround sound multichannel audio. They primarily serve to deliver ambience and diffuse sounds in a film or music soundtrack. Dolby Stereo (1975) was the first standard cinema sound system using a single matrixed mono rear channel (note Disney's Fantasound from the 1930s used a surround channel). Dolby Surround (1982) was the first home audio system to use a rear channel. It and its successor, Dolby Pro Logic (1987), used a single rear surround channel, but often using two speakers connected in anti-phase or a dipole radiator, as shown in the speaker configuration