There are many departments in the building and you feel confused! By opening the entrances from the facade according to purposes, you simply follow the pre-arranged flow.
You are a dog farm owner who manages the properties of all dog breeds. The number of crossbred dogs is increasing every day because of the emergence of new breeds!
In the discussion room without a teacher, you can speak or listen, but when you speak you need to make sure that everyone can hear. Therefore, a loudspeaker is a useful tool.
Undo and redo are common features in editing software. They look simple on the surface, but how do they work internally? How do you design structure and behavior for them?
Have you had a chance to watch The Spy Gone North? The spy infiltrated North Korea's secret locations, and collected its secrets effectively by applying the Visitor Pattern!
