The object of the game is to add a letter to a word, without finishing that or any other word.
Words have to be at least four letters long.
If the first person starts with T , the second added A , and the third added C . If you want to spell Tackle , you add K , you get a letter, because you spelled Tack . If you don't think the person before you is correctly spelling a real word, you can challenge them. If they can't tell you a valid word, they get a letter. If they can, however, you get a letter.