BrownNoiseFlicker<A, B, grade> BrownNoiseFlickerL<B, grade>
Randomly selects between A and B, but keeps nearby pixels looking similar.
https://github.com/profezzorn/ProffieOS/blob/6f8add544c627172ad2dd698c90e5e55078a420a/styles/brown_noise_flicker.h#L4