Point Domino Games
There are three basic types of domino games - block games, point games, and domino games based on card games. The distinguishing characteristic of Point games point games is that they are scored while a hand is in progress, as well as at the end. Typically, scoring is based on the point values of the dominoes making up the ends of the layout. Depending on the game, there may be 2, 3, 4, or even more open ends. The way the points are scored varies from game-to-game, of course.
you can often guess the scoring mechanism based on the name of the game. In All Fives, for example, scoring is based on point values of 5, or of multiples of 5. All Threes is basically the same, except that it uses multiples of 3 for scoring. Threes and Fives bases its scoring on both values.