var BOTTOM_RADIUS = 100;
var MID_RADIUS = 60;
var TOP_RADIUS = 30;



function start(){
    var c1 = new Circle(BOTTOM_RADIUS);
    c1.setPosition(getWidth()/2, getHeight() - BOTTOM_RADIUS);
    c1.setColor(Color.grey);
    add(c1);

    var c2 = new Circle(MID_RADIUS);
    c2.setPosition(getWidth()/2, getHeight() - (BOTTOM_RADIUS*2+MID_RADIUS));
    c2.setColor(Color.grey);
    add(c2);

    var c3 = new Circle(TOP_RADIUS);
    c3.setPosition(getWidth()/2, getHeight() - (BOTTOM_RADIUS*2+MID_RADIUS*2+TOP_RADIUS));
    c3.setColor(Color.grey);
    add(c3);
}