ok i really never got into backgammon. but i never undertood the cube? what is its purpose and how does it work. ive read many things in the rules but nothign really explains it. If i read it correctly you must accept a roll or you lose the game. but then what purpose do pieces on the board mean? if im down 120 pips to 1, i can say Double and win? that makes no sense. little help would be great thanks.