Use the arrow keys to scroll around. Change frequency and amplitude of any of the four octaves to change the properties of the terrain. FOR SPEED Run it here: http://phosphorus.github.io/#46937012
V3 - Now uses precomputed perlin matrix for extra speed. Uses four octaves of Perlin noise ( http://scratch.mit.edu/projects/33521556/ ) to generate the terrain. By default each octave is twice the frequency and half the amplitude - but you can adjust that with the sliders.
