intro_on=new Image();
intro_on.src="images/intro_on.jpg";
intro_off=new Image();
intro_off.src="images/intro_off.jpg";
anim_on=new Image();
anim_on.src="images/anim_on.jpg";
anim_off=new Image();
anim_off.src="images/anim_off.jpg";
sim_on=new Image();
sim_on.src="images/sim_on.jpg";
sim_off=new Image();
sim_off.src="images/sim_off.jpg";
photo_on=new Image();
photo_on.src="images/photo_on.jpg";
photo_off=new Image();
photo_off.src="images/photo_off.jpg";

function animate(imgName)
{document[imgName].src=eval(imgName + "_on.src");}
function animout(imgName)
{document[imgName].src=eval(imgName + "_off.src");}

   tutorialOpen = false;

    function showTutorial() {
      tutorialWindow = window.open("tutorial.html","tutorialWindow","width=520,height=400");
      tutorialWindow.focus();

      tutorialOpen = !tutorialOpen;
    }