If you don't allow that kind of restrictions, many modern bridges should be consider art by that logic because "while looking good and distinct" was one of their design goals.
Precisely. They are both art and engineering -- that's the point. Generally, the art aspect consists of the aesthetic restrictions you've placed on your engineering efforts.
restricting a machine to mechanical operations takes severe engineering effort - what you are doing is just playing with words. you can program to display a time on a watch running Python inside - but you probably would have to research for years before coming up with a reliable and usable mechanical watch - not to mention the advanced features at display here.
