If you look carefully, you can see that the solar clock shows 12 pm, yet the mechanical clock shows 11 am, yet both are right. Let me explain, the solar clock is as the sun depicts, it can not be changed, well not on this stone solar clock, yet the mechanical clock can be altered, as we enter daylight saving.
I like this a lot, it show how time works and how man has altered time to suite his needs, it opens up a lot for both shadow work, surveying and a simple yet fundamental view of our Solar system, the tilt of the earth to the sun, and its effect on weather.
Such a simple photo yet so full of information.
I will use this next year as I teach first year students in both simple surveying and detailing.