A customizable clock that can be used as a powerful tool.
To add a clock widget:
Go to home screen -> tap and hold on an empty space -> select "Apps and widgets" -> (tap on "Widgets" at the top of the screen) -> find, then tap and hold "Analog Clock" widget -> drag the widget to a preferred position on the home screen.
To customize a clock widget or live wallpaper clock:
Open the "Clock" app -> find the clock you want to customize -> Your changes will be automatically saved when You exit the app.