code: def ball(rmax=3, rmin=0, shape=128, limits=[-4, 4], draw=True, show=True, **kwargs):
      
      import ipyvolume.pylab as p3
  
      __, __, __, r, _theta, _phi = xyz(shape=shape, limits=limits, spherical=True)
      data = r * 0
      data[(r < rmax) & (r >= rmin)] = 0.5
      if "data_min" not in kwargs:
          kwargs["data_min"] = 0
      if "data_max" not in kwargs:
          kwargs["data_max"] = 1
      data = data.T
      if draw:
          vol = p3.volshow(data=data, **kwargs)
          if show:
              p3.show()
          return vol
      else:
          return data
docs: Show a ball.