protected static Boolean ExpandPeriodic(CssValueList list) { if (list.Length == 0 || list.Length > 4) { return(false); } if (list.Length == 1) { list.Add(list[0]); } if (list.Length == 2) { list.Add(list[0]); } if (list.Length == 3) { list.Add(list[1]); } return(true); }