Tetris class, TetrisGame class, ScoreBox class and TetrisPiece class . Tetris class is the base class for the game. Each class define a part of Tetris Gameas and knows its position, size, velocity insidethe game. Inside the dir utils main calss is Grid class which encapsulate the instance variable that tell how to build position a given Component within its Container. Component is the superclass of all GUI components in the java.awt package.
Container class inplements a components that can contain other components.
So class Grid is determines component a specified points and produce output rotation of each piece . PosPaintable is interface class which define paint Graphics method very important in this games and implements java.awt. A package utils is group of related and cooperating classes which are utility for tetris games. This is O.K. because the classes are assumed to know about, and trust each other. They specifies the classes in the file of Java source code .