// Click on the image to give it focus 
// and press any key 
 
// Note: the rectangle in this example may 
// flicker as the operating system may 
// register a long key press as a repetition 
// of key presses 
 
void draw() { 
  if (keyPressed == true) { 
    fill(0); 
  } else { 
    fill(255); 
  } 
  rect(25, 25, 50, 50); 
}