//Just trying to pull apart nimitz' spiral from https://www.shadertoy.com/view/MdlXRS
//to see how it works!

#define TAU 6.28318530716

float spiral(vec2 p,float scl, float phase)
{
	float r = length(p);
	r = log(r);
	float a = atan(p.y, p.x);
	return abs(mod(scl*(r-1.0/scl*a) - phase*2.0,TAU)-1.)/2.0;
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
	vec2 uv = fragCoord.xy / iResolution.xy;
    uv -= 0.5;
    float modifier1 = 1.0 / spiral(uv, 1.0, iTime + 2.3);
    float modifier2 = 1.0 / spiral(uv, 2.0, iTime);
    float modifier3 = 1.0 / spiral(uv, 3.0, iTime*2.0 - 1.0);
    float modifier4 = 1.0 / spiral(uv, 25.0 , iTime*5.0 - 2.0);
    vec3 color = vec3 (0.19, 0.43, 0.82);
	fragColor = vec4(color,1.0)
        * (modifier1 +
           modifier2 +
           modifier3 +
           modifier4)/4.0;
}