This clock represents the inner working of a modern cpu in a mechanical manner. Just like a CPU, It contains registers, ALU, memory, Buses, and a Control Unit).  The current hour is read from register A in binary format. The MSB is at the bottom and the LSB is at the top (http://www.youtube.com/watch?v=iFKargQxN8k).

Here is the code that the clock is executing. 

1: CHECK_DTD
2: JUMP 5
3: CLEAR
4: JUMP 1
5: INCREMENT
6: EQUAL 11
7: JUMP 1
8: SET_DTD
9: JUMP 1

For more information see: http://www.liorelazary.com/index.php?option=com_content&view=article&id=46:mechanical-cpu-clock&catid=10:clocks&Itemid=15