A wall at affluent Newton South High School has become an exhibit of college denial letters, a catharsis for one of the most anxious populations around. The Globe reports that, "With each punch of the stapler, each slam of his fist, [student Kellen Mandehr] won a small measure of payback. And a large measure of liberation." As the annual reports from elite schools of "lowest admissions rate ever!" come out, the wall is an oasis......