This clock face, painted by Paolo Ucello in 1443 for the Duomo in Florence is rather unusual in that the numbers are depicted counter-clockwise. The style of the numerals is also interesting (look at the shape of the X). It also appears that the way Ucello chose to write some of the numbers is much more fitting for a clock. In fact, I would recommend to use IIII instead of IV and VIIII instead of IX. This style of numbers requires less space and their progression looks more natural.
