Lloking at the latest Matt Parker video, what he calls “Perlin noise” looks a lot more like Gimp’s “Solid noise” and Wikipedia agrees with him. So why is Gimp/GEGL calling this “solid noise” (which is not understood by Wikipedia) and what is the “Perlin noise” as implemented by Gimp?
According to the source code, the Solid Noise filter is based on a 1989 paper by Dr. Perlin: “Hypertexture” by Perlin and Hoffert – ACM SIGGRAPH HISTORY ARCHIVES
The “Perlin Noise” filter uses code actually written by Dr. Perlin to generate the noise: operations/common/perlin/perlin.c · master · GNOME / gegl · GitLab
So they’re both based on his work, just different variants of it.