jjae:

At the grocery store, if you bought 3 boxes of Kellog’s cereal you’d get a coupon for 1 free gallon of milk.  If 5 boxes, then 2 free gallons, and if 7 boxes, then 3 free gallons.

Few people know it, but Mr.Kellogg was a vegetarian and invented the Kellogg’s Cornflakes to change the meat heavy breakfast eating habits of his times. As we can see, today people eat vegetarian flakes all over the world for breakfast :-)