If you've perused the latest issue of the New Yorker, you may have noticed a rather long letter to the editor about a January cover (by Mark Ulriksen, pictured above). If you didn't, here's how the letter starts:Mark Ulriksen’s “Winter Pleasures,” an impressionistic rendering of Grand Central Terminal’s main concourse, depicts the famous golden clock bathed in sunlight (Cover, January 28th). Note that this can be only an eastward morning scene, not a westward......