void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
        
    vec2 uv = fragCoord/iResolution.xy;   
    float px = (abs(uv.x - 0.5f));
    float py = (abs(uv.y - 0.5f)) * (iResolution.y / iResolution.x);
    
    float k = pow(px, 2.f) + pow(py, 2.f);
        
    k = sqrt(k);
    
    float p = iTime * 5.f;
    
    vec3 col = vec3(
    sin(k * 0100.f - p),
    sin(k * 0030.f - p),
    sin(k * 0700.f - p));
    
    fragColor = vec4(col,1.0);
    
    
}