Last night I attended Caryl Churchill’s play, A Number, at ACT in San Francisco. I found it valuable, challenging, sometimes funny, pithy, and short. A father confronts, one by one, several sons, all but one of them clones. So, they are the same, and different. The father attempts to figure out what mess he created by allowing the cloning, in his incautious desire to have more of “his son.” The sons are working out emotions ranging from a desperate ambition to discover “who they are,” to curiosity and enjoyment of the situation life is presenting.