Fold-ins
Every issue of Mad from 1964 to the present but two has featured a Fold-in, designed by artist Al Jaffee. They usually appear on the inside back cover, though one issue featured a Fold-in front cover and the year-end "Mad 20" issues move the feature to an interior page. In each Fold-in question is asked, often of a topical nature. The subject is illustrated by a picture taking up the bulk of the page, with a block of text underneath. When the page is folded inward, the inner and outer fourths of the picture combine to reveal an alternate answer in both picture and words. Jaffee's precise layouts sometimes include false visual cues designed to trick the reader's eye towards an incorrect solution.
Read more about this topic: Recurring Features In Mad (magazine)