So much for the "p" argument. Soon we will get things moving, literally, with the argument "alpha". But first, some more on how simplex noise is made.
Remember how the noise function was zero at grid points? Those points are fundamental to how the function works. Around each grid point, there is a circular region of influence that adds a little "wiggle" to the surrounding pattern. Each of these wiggles create one diffuse white blob and one diffuse black blob to either side of its associated grid point, and those wiggles summed together is what makes up the noise pattern. This image shows yellow circles around three such regions to make it more clear what their size is. As you can see, the regions of influence overlap, but no more than three of them will overlap at any point.
The function "circle" used to draw the circles is not shown, but it's in the source code for this page if you are curious.
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