Mandelbrot

    double re = -0.235125;
    double imag = 0.827215;
    double r = 4.0e-5;

    const int maxIters = 2048;
    double c_re;
    double c_im;
    double x;
    double y;
    int iteration;
    const double c1 = 4.0/width*r;
    const double c2 = width/2.0*c1;
    const double c3 = height/2.0*c1;
    double xx;
    double yy;

    for(int row = 0; row < height; row++){
        c_im = imag + (row * c1) - c3;
        for(int col = 0; col < width; col++){
            c_re = re + (col * c1) - c2;
            x = 0; y = 0;
            iteration = 0;
            do {
                xx = x*x;
                yy = y*y;
                y = x*y;
                y += y;
                y += c_im;
                x = xx - yy + c_re;
                iteration++;
            }while(xx+yy <= 4 && iteration < maxIters);
            if(iteration < maxIters){
                //Calculate a color from the value of the "iteration" variable and set the pixel color to that
                //I use int rgb = HSBtoRGB((float)iteration/256.0f, 1.0f, (float)iteration/(iteration+8.0f));
                //But idk if that's a thing in JS
            }else{
                //pixel Color = black (RGB 0,0,0)
            }

        }
        PORTD ^= (1 << PD4);
    }