Actually tactically the old "circle the wagons" manuver of the old west cowboys was a "Hollow Square" with the corners rounded off. But you don't normally think of it that way.
Also there were other manuvers which did the same thing and formed a half hollow square such as the 3rd Arkansas at Gettysburg in order to defend itself from flanking fire from their left, refused their left 3 companies 90 degrees to their battle front in order to counter the threat from Union units in the Wheatfield. There are several incidence where Regiment or Brigades refused their flanks to meet threats from their flanks.