Complex sentence: The Tijuana painted donkey or Tijuana Zebra, came about some time in the middle of the twentieth century, the reason for painting the donkeys was to ensure that the animal be seen in photographs.
Split into simpler sentences: The Tijuana painted donkey, or Tijuana Zebra, came about some time in the middle of the twentieth century. The reason for painting the donkeys was to ensure that the animal be seen in photographs.