// add stage listeners 
stage.addEventListener(MouseEvent.MOUSE_DOWN, onDown); 
stage.addEventListener(MouseEvent.MOUSE_UP, onUp); 
 
function onDown(e:Event):void {
 graphics.moveTo(mouseX, mouseY); 
 addEventListener(Event.ENTER_FRAME, onLoop);
}
 
function onUp(e:Event):void {
 removeEventListener(Event.ENTER_FRAME, onLoop);
}
 
// bit shifting colours
function onLoop(e:Event):void {
 graphics.lineStyle((Math.random()*45), Math.random()*0xFFFFFF >> 23, Math.random(), true, "normal"); // blue=black
 graphics.lineTo(mouseX, mouseY);    
}