void setup()
{
size(500,500);
background(122,122,122);
}

void draw()
{
  
}

void mousePressed() {
  if (mouseButton == LEFT) {
    background(122,122,122);
  }
  
  if (mouseButton == RIGHT) {
   background(0,0,0);
  }
  
  if (mouseButton == CENTER) {
   background(255,255,0);
  }

}