def rot90(k=1,axes=[0,1])
      case k % 4
      when 0
        view
      when 1
        swapaxes(*axes).reverse(axes[0])
      when 2
        reverse(*axes)
      when 3
        swapaxes(*axes).reverse(axes[1])
      end
    end
def rot90(k=1,axes=[0,1])
      case k % 4
      when 0
        view
      when 1
        swapaxes(*axes).reverse(axes[0])
      when 2
        reverse(*axes)
      when 3
        swapaxes(*axes).reverse(axes[1])
      end
    end
Rotate in the plane specified by axes.
 @example
   p a = Numo::Int32.new(2,2).seq
   # Numo::Int32#shape=[2,2]
   # [[0, 1],
   #  [2, 3]]

   p a.rot90
   # Numo::Int32(view)#shape=[2,2]
   # [[1, 3],
   #  [0, 2]]

   p a.rot90(2)
   # Numo::Int32(view)#shape=[2,2]
   # [[3, 2],
   #  [1, 0]]

   p a.rot90(3)
   # Numo::Int32(view)#shape=[2,2]
   # [[2, 0],
   #  [3, 1]]