Erika C. answered 08/06/19
The violin is shaped the way it is for a combination of acoustical and ergonomic reasons. The basic rectangular shape and arched body allow for maximum resonance, which was studied and perfected by luthiers like Stradivarius and Amati. The addition of the soundpost is also extremely important as it allows the vibrations of the bridge to be transferred to the body of the instrument (as well as allow structural support along with the bass bar) , which greatly amplifies and enriches the sound of the instrument.
The side cut outs are mostly practical, as it is difficult to play on the E and G strings without them.
The fingerboard and chin rest, likewise, are located where they are for reasons of practicality.
The scroll completely for aesthetic reasons, and it is common to find a variety of different carvings there.
The f-holes allow sound to escape the violin and therefore are necessary. The exact shape, however, could be a variety of different things, although must still work together with the other, more mandatory aspects of the instrument.