A lesson from a father to his impatient son. A beautiful definition of to be father . A test who starts very sad because for viewer all seems clear - the old man, touched by dementia and his poor son giving, again and again, explanation. The same. But it is more. At end, you say - I know the story ! But the beauty , the grace and gentle storytelling are the significant ones. So, a sparrow, a 21 questions and 21 patient answers and another, after a time, three questions.