 However, the distinction is not clear-cut, and many games are also considered to be work (such as professional players of spectator sports or games) or art (such as jigsaw puzzles or games involving an artistic layout such as Mahjong, solitaire, or some video games).Games are sometimes played purely for enjoyment, sometimes for achievement or reward as well.They can be played alone, in teams, or online; by amateurs or by professionals.