# ball.py
class Ball:
    character = "O"

    def __init__(self, position):
        self.position = position
        self.velocity = (1, 1)

    def play_turn(self, game):
        x, y = self.position
        vx, vy = self.velocity
        new_x = x + vx
        new_y = y + vy
        board_x, board_y = game.board_size
        if new_x < 0 or board_x <= new_x:
            self.velocity = (-vx, vy)
        elif new_y < 0 or board_y <= new_y:
            self.velocity = (vx, -vy)
        else:
            self.position = (new_x, new_y)