The Fractal Noise texture node generates a fractal-based pattern (figure 1).
Figure 1: The Fractal Noise node and it's associated parameters
Mode - Specifies whether scalar or vector mode is used to calculate the fractal noise.
Colors 1 & 2 - Specifies the two colors used to generate the fractal noise.
Time - Shifts the fractal pattern over time.
Octaves - Specifies the multiple frequencies in which the fractal pattern is repeated.
Distortion - Determines the scale of random displacement applied to the fractal pattern.
Lacunarity - Controls the size of the space in the fractal texture pattern.
Gain - An amplitude multiplier per iteration where higher values will result in a flatter pattern.
Turbulent - Adds an additional layer of noise to the fractal pattern.
Transform Input - Positions, scales, and rotates the surface texture.
Projection Input - Sets how the texture projects onto the surface.