Processing pixel manip

pixels.processing

void setup() {
  fullScreen();
  frameRate(15);
}

void draw() {
  // Loads all pixels on screen into an array of size width*height
  loadPixels();
  color onColor = #000000;
  color offColor = #FFFFFF;
  for(int x = 0; x<width/2; x++) {
    for(int y = 0; y<height/2; y++) {
      // Calculates a random new coordinate
      // **Bonus points** if the screensaver allows for modifications to the parameter to `random`. Changing the value of one to 4
      // for example, gives another neat effect.
      int x_new = 2*x+int(random(2));
      int y_new = 2*y+int(random(2));

      // If our new coordinate is within the screen flip the color of that pixel.
      if (x_new < width && y_new < height) {
        int dest_pixel = (y_new*width + x_new);

        color c = pixels[y*width+x];

        if(c == onColor){
          pixels[dest_pixel] = offColor;
        }
        else {
          pixels[dest_pixel] = onColor;
        }
      }
    }
  }
  updatePixels();
}