Demoscene visual effect
A classic effect from the era of demoscene (the 80s-90s).
Created by combining sine waves of different frequencies.
f(x,y,t) = sin(x) + sin(y) + sin(x+y+t)
The effect is based on interference of waves.
Each pixel gets a value from the sum of sines:
v = sin(x) + sin(y) + ...
Then the value is translated into a color via a palette (Color Cycling).