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

pixels = W:1024 H:1024

x = from -256 to 256 W
y = from -256 to 256 H

alpha_t = 1253.0

radius = sqrt(x*x + y*y)
phi = atan2(y, x)
beta = 10

phi_r = (radius - alpha_t) / beta

k = abs(cos(phi) - cos(phi_r))
k = if(k < 0.5, 0, k)

r = k
g = k
b = k
	


