A few days ago, we told you about Mark’s Arby’s Roast Beef sandwich which was made with beef-confetti rather than the slices of beef which are normally served. Mark fired off a letter to Arby’s and actually received a reply. In case you were losing sleep thinking about how such an enigmatic sandwich came to be, Arby’s supplies an explanation. Original not-safe-for-lunch photo and Arby’s response, inside…