You may have seen my older post releasing my new coherent noise algorithm (procedural texture & terrain generation primitive, alternative to the artifact-prone Perlin Noise, and alternative to the patent-encumbered Simplex Noise) called OpenSimplex Noise. I've updated the code to include 2D and 4D implementations alongside the 3D implementation, as well as tweaked the gradient set that's being used for the 3D noise.

http://uniblock.tumblr.com/post/99279694832/2d-and-4d-noise-too

As promised, I’ve updated the github gist to include 2D and 4D implementations of OpenSimplex Noise. And in doing so, I also went ahead and changed the gradient set for 3D to something that makes a bit more sense, and is part of a more general scheme that’s being used for all numbers of dimensions of the noise.

Here are some sample renders: 2D (leftmost), a 2D slice of 3D (center), and a 2D slice of 4D (rightmost) https://31.media.tumblr.com/6f9b2cb55741eb87d39dfdce28f59095/tumblr_inline_nd01n5Ipmk1seaucq.png