var loop={
		i:1,
		timer:null,
		pause:function(){
			window.clearTimeout(this.timer);
		},
		again:function(){
			this.invok();
		},
		invok:function(){
			var _=this;
			this.i+=1;
			if(6==this.i){
				document.getElementById('plane_'+(this.i-1)).style.display='none';
				this.i=1;
				document.getElementById('plane_'+this.i).style.display='';
			}else{
				
				document.getElementById('plane_'+this.i).style.display='';
				document.getElementById('plane_'+(this.i-1)).style.display='none';
			}
			this.timer=window.setTimeout(function(){_.invok()},6000);
			}
		};