The outfield is made from thick grass or artificial turf. It is where the outfielders play. The positions to play in the outfield are left, center, and right field (named in relation to the batter's position; thus left field is beyond third base and right field is beyond first base). Outfields vary in size and shape depending on the overall size and shape of the playing field. The outfield stretches from the infield to the outfield wall and it contains the warning track. Outfields especially vary from Little League to major league fields. Little League outfields vary more in size than Major League outfields. Outfields often differ from infields in the specific type of grass used, but most major league outfields are grass.