Initialize a new game, ready to be started with Start().

An event that doesn't cause a change to game state but causes a full redraw; e.g., a window resize.

A Board represents the state of a tetris game board, including the current piece that is descending and the blocks which already exist on the board.

A Game tracks the entire game state of tetris, including the Board, the upcoming piece, the game speed (dropDelayMillis), the score, and various other internal data.

A Tetris piece, including the all the possible rotations, a color, and an index indicating the current rotation of the piece.

A two-dimensional integer-valued vector.

A map from a point on a board to the color of that cell.

A game event, generated by user input or by the game ticker.

A particular rotational instance of a piece.