Dozenal (base twelve) clock and stopwatch timer.
Our time-keeping system uses sub-divison into 60 parts: hours are broken down into minutes, which are further broken into seconds. This was likely decided by the early Egyptians who used base 12 extensively, but still wanted the time units to be friendly to calculations in base 10.
This clock demonstrates how time-keeping would be if we used the original base, and have 5 dozen seconds per minute and 5 dozen minutes per hour.
The first digits are the usal 0-9, and we add X to represent ten and Ԑ to represent eleven.
Another advantage of this system is that the AM/PM distinction is denoted by the higher digit of the hours. Which means, e.g. that "13 o'clock" is always 3 past noon, and you don't have to subtract in your head to convert.
The stopwatch here uses the direction commonly used by mathematicians: rotation from the right-hand position in the positive (counterclockwise) direction.