Simplex noise shrinking near poles

[boytchev]

When simplex noise is used at large scales (e.g. noise(100*x,100*y,100*z)) there is a shrinking of features near poles. The shrinking is noticeable when the scale is more than 1/20 of the horizontal texture resolution. For example, a texture 1024x512 manifests such deformation when the scale is above 50.

https://boytchev.github.io/texture-generator/online/concrete.html?w=512&h=256&s=0&d=100&b=100