This game dates back to the 12th century but its exact origin is unknown. Dominoes is often called "Bones" because the original game tiles were made of of ivory. Each domino has two numbers (or a blank) and each number is arranged like a standard six sided dice. Players take turns playing dominos end to end with the touching numbers matching. The strategy is to make the the outer ring of numbers add up to multiples of five to score points. Dominoes is simple on the surface but riddled with advanced strategy. Hardcore players often "talk smack" in an attempt to distract and intimidate their opponent.