Levers and detents

This is the front view of the clock I blipped yesterday.  Every one of those levers has a specific function.  The serrated lever is called a rack and, when it drops, regulates the number of hours the clock strikes.  Before the invention of the rack, the number of hours struck was determined by a round count wheel with notches cut into it.  This system sometimes meant that the striking could get out of synch with the hour indicated on the dial.  The rack system prevents this from happening.
Horological innovation has been important in that it has permitted the development of many modern technologies.  The levers and cams, in effect, are a way of programming a mechanism to store information to permit a future action.  This became highly developed in the eighteenth century and led to the manufacture of amazingly complicated automata.  The vinyl disc was an innovation that allowed information to be stored in a different way in the grooves of plastic.  The ticker tape used to program the first computers in in a similar line of descent.  It would not fanciful to say that all of modern electronics and information technology can trace their roots back to horological innovation.