3Cs # https://docs.google.com/presentation/d/1zvpwRAHGJwOE9QqhNkLQHHftV6guk7rNxwDQ6RuYhZA/edit#slide=id.g998494e7fd_0_119 https://www.visual-paradigm.com/guide/uml-unified-modeling-language/what-is-activity-diagram/;WWWSESSIONID=C67B13698C795B1642BC5FB95C52D8F8.www1
