public function walkDownTree(aTop:ISprite):void{
                for(var i:int = 0 ; i < aTop.hierarchyChildren.length ; i++){
                    trace(aTop.hierarchyChildren[i].data.id);
                    if(aTop.hierarchyChildren[i].hierarchyChildren){
                        this.walkDownTree(aTop.hierarchyChildren[i]);
                    }

                }
                return true;
            }

        var finished:Boolean = walkDownTree (btop);