anchor.diff:      imag += Cimag;
       r2 = (real * real) + (imag * imag);
   
  -    if (r2 >= 4) {
  +    if (r2 >= 4.0) {
         break;
       }
     }
   
     // Base the color on the number of iterations
  -  float value = fract(iter / 100.0);
  +  float value = fract(iter / (float)iterations);
     vec4 color = vec4(hsv2rgb(vec3(value, 0.8, 0.8)), 1.0);
   
     gl_FragColor = color;
  
positive.code:     // Create button.
      button = new fl.Button(half, 0, width - half, 40, 'Recompile!');
      button.box = fl.FLAT_BOX;
      button.labelsize = 20;
      button.color = fl.DARK2;
      button.callback = (w, _) {
        update();
      };
  
negative.code: }
  
  void main() {
    int iter, iterations = 20;
    float tempreal, tempimag, Creal, Cimag, r2;
  
    vec2 viewport = vec2(viewportHeight, viewportHeight);
  