Cereal Box Design: New Closure | New Republic
http://www.newrepublic.com/article/113319/cereal-box-design-new-closure
But here's something you may not realize (or if you do, it's probably on a subliminal level): There are actually two different types of tabbed box-closure mechanisms out there. One is the kind described above, with a perforated slot. The other format involves two interlocking box flaps that snap together without the need for a perforated slot. You can see the differences between the two designs by looking here.