text: """
  ==============
  Scatter Masked
  ==============
  
  """
  import matplotlib.pyplot as plt
  import numpy as np
  
  # Fixing random state for reproducibility
  np.random.seed(19680801)
  
  
  N = 100
  r0 = 0.6
  x = 0.9 * np.random.rand(N)
  y = 0.9 * np.random.rand(N)
  area = np.pi * (10 * np.random.rand(N))**2  # 0 to 10 point radii
  c = np.sqrt(area)
  r = np.sqrt(x * x + y * y)
  area1 = np.ma.masked_where(r < r0, area)
  area2 = np.ma.masked_where(r >= r0, area)
  plt.scatter(x, y, s=area1, marker='^', c=c)
  plt.scatter(x, y, s=area2, marker='o', c=c)
  # Show the boundary between the regions:
  theta = np.arange(0, np.pi / 2, 0.01)
  plt.plot(r0 * np.cos(theta), r0 * np.sin(theta))
  
  plt.show()
  