float rand(vec2 p)
{
    p = fract(p*vec2(234.51,124.89));
    p += dot(p,p+54.23);
    return fract(p.x);
}

float width = 0.1;

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{    
    int i;
    for(i=0;i<3;i+=1) // Loop over time-shifted color channels
    {
        float t = iTime + 0.1*float(i);
        vec2 pos = 5.*vec2(sin(t*0.2)+0.1*t,cos(t*0.2)+0.1*t);
        vec3 col = 0.1 + 0.3*cos(t+(fragCoord/iResolution.xy).xyx+vec3(0,2,4));

        vec2 uv1 = pos+(5.*(fragCoord-.5*iResolution.xy)/iResolution.y);
        vec2 gv1 = (fract(uv1)-0.5);
        vec2 id1 = floor(uv1);
        vec2 uv2 = pos+2.5*(fragCoord-.5*iResolution.xy)/iResolution.y;
        vec2 gv2 = (fract(uv2)-0.5);
        vec2 id2 = floor(uv2);

        gv1.x *= (float(rand(id1)>0.5)-0.5)*2.;
        gv2.x *= (float(rand(id2+3.)>0.5)-0.5)*2.;

        float mask1 = smoothstep(-0.2,0.2,width-abs(gv1.x+gv1.y-0.5*sign(gv1.x+gv1.y+0.01)));
        float mask2 = smoothstep(-0.2,0.2,width*2.-abs(gv2.x+gv2.y-0.5*sign(gv2.x+gv2.y+0.01)));

        col += mask1;
        col += mask2;
        fragColor[i] = col[i];
    }
    fragColor *= 0.5*dot(fragColor.xyz,fragColor.xyz);
}