#https://www.shadertoy.com/view/ls3XWM

pixels = W:1024 H:1024

x = from -1.0 to 1.0 W
y = from -1.0 to 1.0 H

t = 1.0

d = sqrt(x*x + y*y)
a = atan2(y, x)
k = 0

[loop start:3
aA = 7/3*a + t
rx = fract(a*25/PI)-0.5
ry = 16.0*(d-0.2*sin(aA)-0.5)
dist = smoothstep(0.5,0.0,length2(rx, ry))
k = k + (1+cos(aA)) * dist
a = a + 2*PI
loop end]

r = k/16
g = r
b = r
