wrist-watch design
Watches and their shapes
A mechanical watch is round because it is (traditionally) driven by gears. Which are round. The entire mechanical watch package is predicated on a circular shape. Digital watches are not. Smart watches are based around LCD pixels and integrated circuit packages. These components are rectangular. The smart watch should be rectangular. The form will naturally follow the mechanism. Final design is derived from a set of rules and factors in the system which the product is positioned. Round watches with pixel displays are anachronistic.