def at_range(origin, distance)
      select { |square| Vector.new(origin, square).magnitude == distance }
    end
def at_range(origin, distance)
      select { |square| Vector.new(origin, square).magnitude == distance }
    end
Find all squares at distance of square

 @param [Square] square
   the originating square

 @param [Fixnum] distance
   the specified distance from the square

 @return [SquareSet]
 ==== Example:
   # Get all squares at 2 squares from square_a
   square_set.at_range(square_a, 2)