text: ### create empty tuple:
  empty = ()
  print( empty )
  # ()
  
  ### create tuple with one element - note the trailing comma!
  t = (99,)
  print(t)
  # (99,)
  
  ### create tuple of 3 elements:
  point3d = (4, 0, 3)
  print(point3d)
  # (4, 0, 3)
  
  ### retrieve element feom a tuple
  x = point3d[0]
  print(x)
  # 4
  
  ### attempt to change element in a tuple
  # point3d[0] = 99
  # TypeError: 'tuple' object does not support item assignment
  