5.9.6 Concentric Circles CodeHS

---------------5.9.6 // CODEHS ------------------------
var x = getWidth()/2;
var y = getHeight()/2;
var RADIUS = 200;
function start() {
    var circle = new Circle(RADIUS);
    circle.setPosition(x,y);
    circle.setColor(Color.red);
    add(circle);
    while(RADIUS > 0){
        RADIUS -= 40;
        circle = new Circle(RADIUS);
        circle.setPosition(x,y);
        circle.setColor(Color.black);
        add(circle);

        RADIUS -= 60;
        circle = new Circle(RADIUS);
         circle.setPosition(x,y);
        circle.setColor(Color.red);
        add(circle);

        RADIUS -= 40;
        circle = new Circle(RADIUS);
         circle.setPosition(x,y);
        circle.setColor(Color.black);
        add(circle);

        RADIUS -= -60;
        circle = new Circle(RADIUS);
         circle.setPosition(x,y);
        circle.setColor(Color.red);
        add(circle);
        RADIUS -= -20;
        circle = new Circle(RADIUS);
         circle.setPosition(x,y);
        circle.setColor(Color.red);
        add(circle);

    }
}