Blue noise
Noise whose energy sits in the high frequencies, with no low-frequency clumps — the points spread evenly but irregularly, with neither a pattern nor clustering.
White noise contains every frequency equally and so forms random clumps and gaps; to the eye it looks dirty. Blue noise is the opposite: the name borrows from light, where blue is the high-frequency end. By suppressing the low frequencies, the samples spread as evenly as randomness allows without falling into a visible grid — the same property a Poisson-disk distribution has.
Robert Ulichney coined the term in 1987 and in 1993 published the void-and-cluster method for precomputing noise textures. In graphics, blue noise is used for dithering, stippling and placing sample points so the error is visually invisible rather than lumpy. Unlike gradient functions such as simplex noise and Worley noise, which generate patterns, blue noise is about how individual samples are distributed.