Alive and Kicking



Da Vinci's cam hammer was covered briefly here. This object was the "object of the day" during the Creative Automata class at UT Dallas (Jan 22, 2014). At the start of each class, students are shown an object from real life in a photograph or perhaps from an illustration. In this case, the object is a picture of a kit model that I made and later stained. The physical model was handed out during class for handling and observation. The driving question is "What information do you see?" This question elicited a wide number of expected and completely unexpected responses, all of which were welcome since this exploration is how we communicate and learn about computing. The first comment was that there was a conditional branch on the snail cam. You can see the cam driving the follower (the rigid linkage that connects to the hammer on the right side). When the follower makes contact with this discontinuity in the cam, the rising hammer falls, causing a change in state (another type of information flow---of control). Someone said that there was a stack (a type of data structure similar to a stack of plates), but when we went looking for the stack, it was not clear that one existed. The support structures for the cam shaft are inverted ternary trees of height one. Seeing information--in an ancient machine. However, the technology goes much further back than Da Vinci in what were called trip hammers written about by the Chinese in 40BC in the Ji Jiu Pian dictionary. So, foundations for computing were were alive and kicking early on with hammers.