Without wanting to sound too much like Professor Brian Cox, time is something that is absolutely fundamental to humans as a species our whole lives are based around the concept, and having a clock on your person at all times is pretty much essential. Time is also important in the Minecraft world too, given that monsters usually appear at night and as it turns out, making a real-time, working analogue clock is absolutely within the realms of possibility. The clock comes complete with working hour, minute and second hands, all of which circulate the clock face and display an accurate time. The inner mechanisms of the machine are naturally incredibly complicated and quite hard to understand for anyone who isnt an expert in making these sorts of things, but the central time-tracking and hand placement system for the clock uses over 2500 command blocks something that a lot more people can understand and marvel at. You might not think its the most interesting creation ever made in Minecraft but its an astonishing piece of engineering, and one that shouldnt be looked down on just because its an everyday item.