Editing Perlin noise (section)

===Grid definition===
[[File:PerlinNoiseGradientGrid.svg|alt=|none|thumb|256x256px|A two-dimensional grid of gradient vectors]]
Define an {{mvar|n}}-dimensional grid where each grid intersection has associated with it a fixed random {{mvar|n}}-dimensional unit-length gradient vector, except in the one dimensional case where the gradients are random scalars between −1 and 1.