void setup
{
  d = createShape(); // d is a PShape
  d.beginShape();
  fill(100);
  rect(200,200,200,200);

  d.endShape(CLOSE);
  d.disableStyle()
}

void draw()
{
  shape(d, 300, 250);
    if ( mouseX >= 0 && mouseX <= 600 && mouseY >=0 && mouseY <= 600 )
   {
       greenC = true;   //a boolean
    }
}

public void mousePressed()
{
   if ( greenC )
   {

     d.disableStyle();
     d.setFill(0);

 }
}