Kenneth Lonergan’s Margaret, which suffered a snuff theatrical release last autumn, bows on home video next week, in a Blu-ray/DVD combo pack that includes an additional director’s cut. But the movie isn’t named for Anna Paquin’s lead character. It’s actually based on a poem by Gerard Manley Hopkins. So the poem is entitled “Margaret,” right? Well, no… it’s actually called “Spring and Fall.” But here, let this interactive study guide, with film clips, explain the connections.