tween or morph many elements based on css class selector using mootools?

how do i tween/morph the height of many e开发者_开发技巧lements at once selected by css class selector using mootools?

thanks :)

Basics of MooTools:

$$('div').each(function(el, index){
    el.morph({
        height: 100 * index
    });
});​

Example: http://jsfiddle.net/mbrNq/