The idea of "The Exquisite Corpse" is that 4 people collaborate in the creation of a piece of artwork. The first person creates the first (topmost) "slice", an unfinished artwork.
The second person receives the bottom section (15 X 450 pixels) of the top slice. They work from the little information that slice provides and create the second "slice". The 3rd and 4th participants receive the thin section of the slice before them and create their "slices". When the last slice is completed and submitted, the image is placed together for the first time and the participant get to see how successful their collaborative effort is.