UML sequence diagram - Checking process

"A schedule or timetable is a basic time management tool consisting of a list of times at which possible tasks, events, or actions are intended to take place, or a sequence of events in the chronological order in which such things are intended to take place. The process of creating a schedule - deciding how to order these tasks and how to commit resources between the variety of possible tasks - is called scheduling, and a person responsible for making a particular schedule may be called a scheduler. Making and following schedules is a fundamental human activity, and learning to do these things effectively is one of the most basic life skills. There are a wide variety of situations in which schedules are necessary, or at least useful.
Schedules are useful for both short periods, such as a daily or weekly schedule, and for long term planning with respect to periods of several months or years. They are often made using a calendar, where the person making the schedule can note the dates and times at which various events are planned to occur. Schedules that do not set forth specific times for events to occur may instead list an expected order in which events either can or must take place." [Schedule. Wikipedia]
The UML sequence diagram example "Checking process" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"The iPhone ... is a line of smartphones designed and marketed by Apple Inc. It runs Apple's iOS mobile operating system. ...
The interface is based around the home screen, a graphical list of available applications. iPhone applications normally run one at a time. Starting with the iPhone 4, a primitive version of multitasking came into play. Users could double click the home button to select recently opened. However, the apps never ran in the background. Starting with iOS 7, though, apps can truly multitask, and each open application runs in the background when not in use, although most functionality is still available when making a call or listening to music. The home screen can be accessed at any time by a hardware button below the screen, closing the open application in the process.
By default, the Home screen contains the following icons: Messages (SMS and MMS messaging), Calendar, Photos, Camera, YouTube, Stocks, Maps (Google Maps), Weather, Voice Memos, Notes, Clock, Calculator, Settings, iTunes (store), App Store, (on the iPhone 3GS and iPhone 4) Compass, FaceTime and GameCenter were added in iOS 4.0 and 4.1 respectively. In iOS 5, Reminders and Newsstand were added, as well as the iPod application split into separate Music and Videos applications. iOS 6 added Passbook as well as an updated version of Maps that relies on data provided by TomTom as well as other sources. iOS 6 also added a Clock application onto the iPad's homescreen. However, it also no longer support YouTube. Docked at the base of the screen, four icons for Phone, Mail, Safari (Internet), and Music delineate the iPhone's main purposes." [iPhone. Wikipedia]
The example "iPhone OS (iOS) graphic user interface (GUI) - SMS application" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Graphic User Interface solution from the Software Development area of ConceptDraw Solution Park.