#define iterKifs 500.
#define time iTime*.25

//someone elses shader, modified by ollj
//source lost, may even be from glslsandbox.

#define dd(a) dot(a,a)
vec2 ddm(mat2 a){return vec2(dd(a[0]),dd(a[1]));}
vec3 ddm(mat3 a){return vec3(dd(a[0]),dd(a[1]),dd(a[2]));}
vec4 ddm(mat4 a){return vec4(dd(a[0]),dd(a[1]),dd(a[2]),dd(a[3]));}
#define u5(a)((a)*.5+.5)
#define u2(a)((a)*2.-1.)
vec2 c2(vec2 a){return a*vec2(1,-1);}
vec2 cs(vec2 a){return vec2(cos(a.x),sin(a.y));}
float suv(vec2 a){return a.x+a.y;}
float suv(vec3 a){return a.x+a.y+a.z;}
vec2 suv2(vec4 a){return vec2(suv(a.xy),suv(a.zw));}//sum modulo 2
vec4 abab(float a,float b){return vec4(a,b,a,b);}

float evalDx(float a,vec4 b){return((a*b.w+b.z)*b.y)+b.x;}
float rt(float a,vec3 b){return evalDx(a,b.yzxz);}

#define ViewZoom 1.
#define fra(u) (u-.5*iResolution.xy)*ViewZoom/iResolution.y
vec2 fra2(vec2 u){float r=iResolution.x/iResolution.y;u-=.5;u*=ViewZoom;u.x*=r;return u;}//fra2(u)=fra(u*iResolution)

float random(float x) {
    return fract(sin(x) * 43758.5453123);
}

// Symmetry function
float symmetry(float value, float axis) {
    return 0.5 * (value + sign(axis) * value);
}

vec3 neonColors(float t) {
    return vec3(
        0.5 + 0.5 * sin(t * 3.0),
        0.5 + 0.5 * sin(t * 3.0 + 0.7),
        0.5 + 0.5 * sin(t * 3.0 + 1.4)
    );
}


void mainImage( out vec4 O, in vec2 U ){
    // Retrieve audio input data from iChannel0
    float audioAmplitude = texture(iChannel0, vec2(0.5)).r;

    vec2 m=(U.xy-iResolution.xy/2.0)/min(iResolution.y,iResolution.x)*30.;
    mat2 w=mat2(m,m);
    m=(time+360.)*vec2(.1,.3);
    vec2 mspt=(vec2(suv(sin(m.x*vec3(1,.5,1.3)))+suv(cos(m.x*vec2(-0.4,.2))),
                    suv(cos(m.x*vec3(1,.8,1.5)))+suv(sin(m.x*vec2(-1.1,.1))))+1.)*.35;
    vec3 r=vec3(0.);
    float Z=.4+mspt.y*.3, n=.99+sin(time*.03)*.003, a=(1.-mspt.x)*.5;
    vec2 u=cs(suv2(vec4(.024,.23,.03,.01)*abab(m.y,a)))*vec2(3.1,3.3);
    vec2 t=1.1*cs(suv2(vec4(.03,.01,.033,.23)*abab(m.y,a)));

    for(float i=0.; i<iterKifs; i++){
        vec2 p=vec2(dd(w[0]),dd(w[1]));
        if(p.y>1.) w[1]/=p.y; if(p.x>1.) w[0]/=p.x;
        p=mix(1./p,p,step(p,vec2(1.)));
        r.x=evalDx(r.x,vec3(p,n).yzxz);
        if(i<iterKifs-1.){
            r.y=evalDx(r.y,vec3(p,n).yzxz);
            if(i<iterKifs-2.) r.z=evalDx(r.z,vec3(p,n).yzxz);
        }
        w[0]=vec2(dot(w[0],c2(t)),dot(w[0],t.yx))*Z+vec2(.033,.14);
        w[1]=vec2(dot(w[1],c2(u)),dot(w[1],u.yx))*Z-vec2(.023,.22);
    }

    vec3 s=fract(r);

    // Apply symmetry to the pattern with enhanced detail
    s.x = mix(s.x, s.y, step(0.5, mod(U.x, 1.0)));
    s.y = mix(s.y, s.x, step(0.5, mod(U.y, 1.0)));

    // Enhance fractal illusion with intricate neon colors
    vec3 neonColor = neonColors(time * 5.5);

    // Apply audio reactivity with emphasis on bass frequencies
    float audioReactivity = pow(audioAmplitude, 2.0) * 5.0;
    s.rgb += neonColor * audioReactivity;

    s -= u5(sign(mod(r, 2.) - 1.)) * u2(s);
    O = vec4(s, 1.);
}