text: #!/usr/bin/python
  import urllib2
  import sys
  import cv2.cv as cv
  import numpy
  
  if __name__ == "__main__":
      cv.NamedWindow("camera", 1)
  
      capture = cv.CaptureFromCAM(0)
  
      paste = cv.CreateMat(960, 1280, cv.CV_8UC3)
      topleft = numpy.asarray(cv.GetSubRect(paste, (0, 0, 640, 480)))
      topright = numpy.asarray(cv.GetSubRect(paste, (640, 0, 640, 480)))
      bottomleft = numpy.asarray(cv.GetSubRect(paste, (0, 480, 640, 480)))
      bottomright = numpy.asarray(cv.GetSubRect(paste, (640, 480, 640, 480)))
  
      while True:
          img = cv.GetMat(cv.QueryFrame(capture))
  
          n = (numpy.asarray(img)).astype(numpy.uint8)
  
          red = n[:,:,0]
          grn = n[:,:,1]
          blu = n[:,:,2]
  
          topleft[:,:,0] = 255 - grn
          topleft[:,:,1] = red
          topleft[:,:,2] = blu
  
          topright[:,:,0] = blu
          topright[:,:,1] = 255 - red
          topright[:,:,2] = grn
  
          bottomright[:,:,0] = red
          bottomright[:,:,1] = grn
          bottomright[:,:,2] = 255 - blu
  
          fgrn = grn.astype(numpy.float32)
          fred = red.astype(numpy.float32)
          bottomleft[:,:,0] = blu
          bottomleft[:,:,1] = (abs(fgrn - fred)).astype(numpy.uint8)
          bottomleft[:,:,2] = red
  
          cv.ShowImage("camera", paste)
          if cv.WaitKey(6) == 27:
              break
      cv.DestroyAllWindows()
  