function rotateImages(i) {

    if (i==0) {

       document.images[2].src = "images/tn_beam.jpg";
       document.images[3].src = "images/tn_boxculvert.jpg";
       document.images[4].src = "images/tn_truck.jpg";
       setTimeout("rotateImages(1)", 10000);

    } else {

       document.images[2].src = "images/tn_pipes.jpg";
       document.images[3].src = "images/tn_pipes2.jpg";
       document.images[4].src = "images/tn_firerings.jpg";
       setTimeout("rotateImages(0)", 10000);

    }

}