The clock has been for a long time more than a means of knowing the time - it is a piece of art. A good example for this is "The clock I can't see". It is a round ceramic clock filled with red and green circles. Between the circles some numbers are hidden: 12, 3, 6 and 9. It's quite obvious that the colorblind people can't see the numbers. The idea is nice and hopefully no colorblind person will feel offended.
See the official page