Pick a pale line on a dark chalk-stripe jacket and follow it down with your eye. For several inches the going is easy. Then the line reaches a pocket and has a decision to make. It may carry on so quietly that the pocket nearly vanishes. It may stop beneath a flap. On an angled opening it can seem to take a small step sideways. Much of the character of a striped jacket lives in that inch of cloth. Start with a patch pocket. A separate piece of cloth sits on top of the jacket front, so you can see…