A square wave is a type of waveform that alternates between two levels, typically high and low, creating a shape that resembles a series of squares. This waveform is commonly used in electronics and signal processing because it can easily represent digital signals, where the two levels correspond to binary values of 1 and 0. Square waves are often generated by devices like oscillators and can be found in various applications, including audio synthesis and clock signals in computers. Their sharp transitions make them useful for testing and controlling circuits, as they can quickly switch states without gradual changes.