[Zik.]

var xl:Number = -1;
var yl:Number = -1;
function go(i:Number):Void {
	attachMovie("line_mc","line_mc_"+i,i,{_x:xl, _y:yl});
	xl = xl+4;
	if (yl == -1) {
	       yl = -5;
	} else {
	       yl = -1;
	}
}
for (var i = 1; i <= 140; i++) {
	setTimeout(go, 100 * i, i); //время сами зададите
}