Ludo is an ancient Indian strategy board game for two to four players,
in which the players race their four tokens according to the rolls of
a single die. To enter a token in to the race, a player must roll a
6. If the advance of a token ends on a square occupied by another
player's token, the other player's token is taken out of the race. the
returned token can enter the race again only when the owner rolls a
6.