I was watching TV one day when I noticed a certain effect in a commercial. The Center Folding effects were the result of that inspiration. The Accordion Folds were inspired by the folding used in the Center Folding transitions.
So, there are 6 variations each of the Center Folding and Accordion Folds transitions for 16:9 Widescreen show in ProShow Producer 5+
Find them here: Folds