What is the effect of using still photographs for the stylistic system of La Jete?

Answer the following questions (approx. 500 words):
What is the effect of using still photographs for the stylistic system of La Jete? How does this contribute to the narrative, and how does it affect your interpretation of the film?
How are Ballet Mchanique and Koyaanisquatsi different? How are they similar? Explain.
How would you interpret Koyaanisquatsi? Is this an experimental film? A documentary?