text: '''
  ==============
  3D scatterplot
  ==============
  
  Demonstration of a basic scatterplot in 3D.
  '''
  
  from mpl_toolkits.mplot3d import Axes3D
  import matplotlib.pyplot as plt
  import numpy as np
  
  
  def randrange(n, vmin, vmax):
      '''
      Helper function to make an array of random numbers having shape (n, )
      with each number distributed Uniform(vmin, vmax).
      '''
      return (vmax - vmin)*np.random.rand(n) + vmin
  
  fig = plt.figure(figsize=(10, 8))
  ax = fig.add_subplot(111, projection='3d')
  
  n = 100
  
  # For each set of style and range settings, plot n random points in the box
  # defined by x in [23, 32], y in [0, 100], z in [zlow, zhigh].
  for c, m, zlow, zhigh in [('r', 'o', -50, -25), ('b', '^', -30, -5)]:
      xs = randrange(n, 23, 32)
      ys = randrange(n, 0, 100)
      zs = randrange(n, zlow, zhigh)
      ax.scatter(xs, ys, zs, c=c, marker=m)
  
  ax.set_xlabel('X Label')
  ax.set_ylabel('Y Label')
  ax.set_zlabel('Z Label')
  
  plt.show()
  