old_contents: #Interference from two holes.
  import matplotlib.pyplot as plt
  import LightPipes
  from LightPipes import cm, m, mm, nm, um
  
  
  LP=LightPipes.Init()
  
  wavelength=20*um
  size=30.0*mm
  N=1000
  LP.version()
  F=LP.Begin(size,wavelength,N)
  F1=LP.CircAperture(0.15*mm,  -0.6*mm,0, F)
  F2=LP.CircAperture(0.15*mm,  0.6*mm,0, F)
  F=LP.BeamMix(F1,F2)
  F=LP.Fresnel(30.0*cm,F)
  I=LP.Intensity(2,F)
  plt.imshow(I); plt.axis('off');plt.title('intensity pattern')
  plt.show()
  
new_contents: #Interference from two holes.
  import matplotlib.pyplot as plt
  
  from LightPipes import *
  
  wavelength=20*um
  size=30.0*mm
  N=200
  print(LPversion)
  #F=Begin(size,wavelength,N)
  #F1=CircAperture(0.15*mm,  -0.6*mm,0, F)
  #F2=CircAperture(0.15*mm,  0.6*mm,0, F)
  #Use the PointSource command for versions >=1.2.0
  F1=PointSource(size,wavelength,N,-0.6*mm,0)
  F2=PointSource(size,wavelength,N,0.6*mm,0)
  F=BeamMix(F1,F2)
  F=Fresnel(30.0*cm,F)
  I=Intensity(2,F)
  plt.imshow(I); plt.axis('off');plt.title('intensity pattern')
  plt.show()
  
subject: Update Young.py