to_remove = Make an (empty) list of squares to not keep
squares = Create a square for each point, with the point as its center

For each square in squares
  If the square has more than one point in it
    For each of the points in this square that aren't the center point
      temp_list = intersect(points_in_this_square, points_in_other_point's_square)
      If sort(temp_list) == sort(points_in_this_square)
        to_remove = append(to_remove, other_point)

squares = squares not in to_remove