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

pixels = W:1024 H:1024

x = from 0 to 1 W
y = from 1 to 0 H

r = mix(0.6, 1.0, y)
g = mix(0.0, 1.0, y)
b = mix(1.0, 0.3, y)

i = 3

w = sqrt(y*i+1.0+cos(x*i+i))*0.7
px = cos(x*i)*w
py = cos(x*i+1.6)*w

[Loop Start:20
tx = reflect2d_x(px, py, py, px) + px*0.14
py = reflect2d_y(px, py, py, px) + py*0.14
px = tx
Loop End]

d = px*px + py*py

r = if(d<3, 0, r)
g = if(d<3, 0, g)
b = if(d<3, 0, b)
