function Engine() {
    //privileged
    this.load = function(what, id, params) {
    
        switch (what) {
            case 'button':
                loadButton(id, params);
        }
    }

    //private
    function loadButton(id, init) {
        var o,p,i;
        var property, value;
        o = document.getElementById(id);
        p = new Slideball();
        p.init(o,init);
    } 
}