The player presses the Mah Jongg button when they have Mah Jongg or are calling a tile for Mah Jongg.  The app may call Mah Jongg for you if you draw it. The app may also show a green MahJongg button if you have Mah Jongg or can call a tile for Mah Jongg.  If you have Mah Jongg, press the MahJongg button to declare it (no discard is needed).  After a player calls Mah Jongg, all players’ hands and text indicating the hand they were trying to make are shown.  Each player’s score is also shown.  Hands without a joker (except singles and pairs) score double the card’s base value for that hand from all players.  A player that draws the Mah Jongg tile rather than calling it, also scores double from all players.  Otherwise, only the player that discarded the tile called for Mah Jongg loses double.  The game also keeps track of the primary player’s highest score ever received in a single game and the total accumulated score across games.  If the tiles run out before anyone calls Mah Jongg, it is called a “wall game” and nobody scores.