var Kuh = new Image();
    Kuh.src = "images/bullet_kuh.gif";
    var Pferd = new Image();
    Pferd.src = "images/bullet_pferd.gif";
    var Schaf = new Image();
    Schaf.src = "images/bullet_schaf.gif";
    var Gelb = new Image();
    Gelb.src = "images/bullet_gelb.gif"