Picture puzzle: What is very unusual about this clock?

"There is a story that a famous clockmaker had constructed a clock for Louis XIV, king of France. The clockmaker had naturally used IV for four.   

When the clock was shown to the king, he remarked that IIII should have been used instead of IV. When it was explained to him that IV was correct, he still insisted, so that there was nothing to do but change the clock dial. This introduced the custom of using IIII for four.

This is probably only a story, however, as IIII occurs long before the time of Louis XIV. And this same story is also told in connection with other monarchs.

There is one reason why IIII is preferable to IV, and it may have caused the change. On the other side of the clock dial the VIII is the heaviest number, consisting of four heavy strokes and one light one, as it is usually made. It would destroy the symmetry to have the IV with only two heavy strokes on the other side. Thus, IIII with four heavy strokes is much to be preferred. The change may therefore have been made for reasons of symmetry."

From Time & Timekeepers, W. I. Milham, The Macmillan Company, New York, 1947, p. 196:

* You can see this clock opposite Owls Nest Books off Elbow Drive S.W., in Calgary, Alberta.