An arbitrary-dimensional noise generator; it's not suitable for real-time use, but could be very useful when used
with unconventional axes, particularly during level generation. It produces smooth, non-artifact-prone gradient noise
with lots of rounded "raindrops on a window" shapes. It is very biased toward central results (near 0.0) and only
rarely returns results near -1.0 or 1.0, the extremes of its range.
Sample of 2D MitchellNoise.
Created by Tommy Ettinger on 11/6/2019 using
code by Donald Mitchell.