Number Triangle: Make 15

- The properly formed triangles will disappear from the board.
- The player advances to the next level if there are no numbers left on the board, if they fail, they can replay that round one more time.
- The player has to go back to the lower level or to start a new game if their two attempts at a level ( including 'REPLAY') are unsuccessful.
- The game ends when the player accomplishes the eighth level.
* Trios of fifteen: (1,5,9);(1,6,8);(1,7,7);(2,4,9);(2,5,8);(2,6,7);(3,3,9);(3,4,8);(3,5,7),(3,6,6);(4,4,7);(4,5,6);(5,5,5)