function start(){
    var rectWidth = getWidth()/3;
    var rectHeight = getHeight();

    var greenRect = new Rectangle (rectWidth, rectHeight);
    greenRect.setPosition (0,0);
    greenRect.setColor (Color.green);
    add(greenRect);
    //green rectangle

    var redRect = new Rectangle (rectWidth, rectHeight);
    redRect.setPosition (rectWidth*2, 0);
    redRect.setColor (Color.red);
    add(redRect);
    //red rectangle
}