void setup()
{
  size(250, 250);
  noStroke();
  framerate(100);
}

int frame = 0;

void draw()
{
  frame++;
  background(0);
  fill(255);
  rect(frame % (width * 2) - width, frame % (height * 2) - height, width, height);
    
  print("<FRAME: " + (frame) + ">");
  if (frame > 2000 && frame % 16 < 8)
    println();
}

void mousePressed()
{
  System.err.println("MOUSE(" + mouseX + ", " + mouseY + ")");
}