rotate_image = new Image	
		var show
		var previous
		var next
		var navImages = new Array("cubhis_technician2.jpg",
								 "cubhis_technician3.jpg",
								 "cubhis_technician.jpg",
								 "cubhis_bridge.jpg",
								 "cubhis_computer.jpg",
								"cubhis_garden.jpg",
								"cubhis_lab2.jpg",
								"cubhis_lab3.jpg",
								"cubhis_lab4.jpg",
								"cubhis_lab5.jpg",
								"cubhis_lab6.jpg",
								"cubhis_lab7.jpg",
								"cubhis_lab.jpg",
								"cubhis_library2.jpg",
								"cubhis_library.jpg",
								"cubhis_staff2.jpg",
								"cubhis_staff.jpg"
											);
		var numImgs=navImages.length;
		var ran_number = Math.floor(Math.random() * numImgs);