This is the archetypal fractal used when generating perlin noise. It works
simply by adding successive values together to create a final value. As the
succesive values are often calculated at increasing frequencies and the
strength is often decreasing, it will create the impression of ever-smaller
details as you zoom in. This function is intended to be used in conjunction
with fracture()
fbm(base, new, strength, ...)
The prior values to modify
The new values to modify base
with
A value to modify new
with before applying it to base
ignored