I find unequal hours [0] interesting.

Basically, day (from sunrise to sunset) and night (sunset to sunrise) are each divided into 12 equal periods. But night hours and day hours are, of course, not equal to each other and changing throughout the year.

You can make a computer implementation by pulling astronomical sunset/sunrise times for a specific geographical location and then it's a simple arithmetic to convert from modern hours to horae temporales

[0] https://en.wikipedia.org/wiki/Unequal_hours