Some thermite-like mixtures are used as pyrotechnic initiators in fireworks. Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. The use of fireworks may lead to dangerous pyrotechnic incidents. It does not contain an explosive or pyrotechnic filler of any kind. Solid propellants are usually ignited with one-shot pyrotechnic devices. Currently produced engines are ignited with a pyrotechnic ignition system. The government contracted match factories to manufacture gunpowder and pyrotechnic fillers like tracers. Flares produce their light through the combustion of a pyrotechnic composition. Flares may be colored by the inclusion of pyrotechnic colorants. The charge also ignites a second pair of pyrotechnic delays. Barium sulfate is commonly used as a component of "strobe" pyrotechnic compositions. Gallic acid is a component of some pyrotechnic whistle mixtures. Methods of ignition include pyrotechnic, electrical (spark or hot wire), and chemical. The book provided the standard designs for creating rockets, fireballs, and other pyrotechnic devices. A PIC single-channel capacitor discharge device controls the firing of each pyrotechnic device.