#https://www.shadertoy.com/view/Ms3SzB

pixels = W:1024 H:1024

x = from 0 to 5 W
y = from 0 to 5 H

kx = ceil(x)
ky = ceil(y)

x = 2*fract(x) - 1
y = 2*fract(y) - 1

a = atan2(y, x)
r = length2(x, y)
v = 0.0
t = 456.23

[loop start: 1
b = kx/ky*a + t
v = max(v, (1 + 0.8* cos(b))/1.8)
a = a + 2*PI
loop end]

r = v*0.8
g = sqrt(v)
b = v*0.3
