Waveforms have different shapes that affect the way they sound. A sine wave has a smooth, curved shape and produces a clean, pure tone with no extra harmonics. A square wave has a sharp, blocky shape that switches suddenly between high and low, creating a buzzy, hollow sound. A sawtooth wave has a ramp-like shape that rises or falls in a straight line, giving it a bright, harsh sound full of harmonics. A triangle wave has a pointed, zig-zag shape with smoother transitions than a square wave, and it sounds mellow and soft. Below are examples of each.