Edited by Jane Rosemarin
The Inside Out Envelope. Designed and folded by William Zicker. See PDF diagrams.

The process of design — in origami and other fields — can yield artistic creations as well as useful inventions. Limitations can be a catalyst for creativity, and this model meets the goal of being a secure envelope that uses the paper efficiently and has clean surfaces with hidden seams. Fewer, smaller folds provide more volume in the final product. The perpendicular folds in three dimensions provide counteracting stresses that keep the folds in place.

The title, Inside Out Envelope, refers to this envelope being formed by hidden, internally rolled seams that are locked in place by a cuffed top.

By adding pleats or combining multiple panels, folders can create their own variations.

Some Variations

Two envelopes nested. The inner envelope is folded with slightly larger seams so it fits smoothly into the outer envelope. Idea: William Zicker. Folded by Jane Rosemarin.
A wider top hem is lifted on one side to form a flap. Idea and folding by David Einheber.
One pleat is opened before the top hem is turned in so that a gusset is formed. Idea and folding by Jane Rosemarin.