The intersection of Missouri 28 and US 63 south of Vienna forms a triangle. Approaching the intersection from the south on Missouri 28, the eastern part of the triangle is marked as Missouri 28. The western part is marked as US 63, but MoDOT county maps show it as Spur 28. In the other direction, that leg of the triangle is marked as Missouri 28 and not as a spur. It's probably done this way because each leg of the triangle is relatively short, probably less than 500 feet each way.