var color = new Array('#fff', '#ff0', '#f00', '#000', '#00f', '#0ff');if(window.DeviceMotionEvent) {    var speed = 25;    var x = y = z = lastX = lastY = lastZ = 0;    window.addEventListener('devicemotion', function(event){        var acceleration = event.accelerationIncludingGravity;        x = acceleration.x;        y = acceleration.y;        if(Math.abs(x-lastX) > speed || Math.abs(y-lastY) > speed) {            document.body.style.backgroundColor = color[Math.round(Math.random()*10)%6];        }        lastX = x;        lastY = y;    }, false);}