The game starts by arranging marbles on the board. Exactly one slot is empty, traditionally the center slot.
A move is made by making one marble jump over exactly one marble and land in an empty slot exactly two positions away. When such a move is made, the marble that is jumped over is removed. Therefore, each single valid move increases the number of empty slots by one. A marble can only jump orthogonally (i. e. horizontally or vertically). The game ends when no more valid moves can be made. At any point in the game, the score is the number of marbles on the board. The objective of the game is to make moves so as to end up with the minimum score when the game ends.
In this assignment you will write the model for this game. The model will maintain the state of the game and allow a client to specify moves. You are not required to make the game playable at this point.