There were two cows in a field. The first cow said "moo" and the second cow said "baaaa." The first cow asked the second cow, "why did you say baaaa?" The second cow said, "I'm learning a foreign language."
Six: two to screw in the bulb and four to testify that it was lit from the moment they began screwing.
None; the bulb will change itself when it is ready.