Eggbox pattern · verified flat-foldable
The Nine Hollows
This family is not rigid-foldable — the paper has to bend on the way, so there is no continuous 3D motion to show. Step diagrams are the honest way, and the way every origami book does it.
Open the diagram sheet →How to fold it
- Print the grid sheet at 100% and cut cleanly along its outer border
- Working corner to corner, score every printed line with a ruler and an empty ballpoint before making any fold
- Accordion the orange solid lines first, working across the grid so all 18 mountain creases stand up in sequence
- Now fold the closed strip along the blue dashed family, alternating each of the 6 valley creases the opposite way
- Open the sheet flat and check every intersection, correcting any crease that leans against its printed colour
- Close and open the whole grid a few times, letting the paper settle into its final folding range.
Pre-creasing every line before you collapse is the whole trick. Paper remembers.
The story below, read word for word by a synthetic voice over this fold's own music.
At the Tuesday market the egg seller keeps a stack of empty cartons behind her stool, flattened and tied with string, waiting for whoever wants them. Children ask for one and get it. They carry it home held out in front of them like something that might spill.
What they do with it, mostly, is press their fingers into the hollows. There is a pleasure in a surface that rises and falls in an order you can predict with your hand before your eye has finished reading it. That surface, drawn in paper rather than moulded pulp, is what people mean when they say the eggbox pattern.
Where the Shape Comes From
No one signed this fold. It appears in packaging workshops, in engineering notes on doubly curved surfaces, in the folded paper exercises passed between teachers who learned it from someone who learned it from someone. It is traditional and free for anyone to fold, sell, teach, or reinvent. What this page carries is narrower: our measurements, our step diagrams, the story, the music, the recording.
The fold has a stubborn quality that separates it from most of what we publish. The facets do not stay flat while the sheet moves. If you built this in rigid panels connected by hinges, the mechanism would lock before it went anywhere; the sheet gets from open to closed only because paper is willing to bow slightly along the way. Engineers call that behaviour non-rigid, and it is the reason the surface can take on curvature in two directions at once, dishing and doming across the same piece.
That stubbornness changed how we made this page. A smooth animation of the closing motion would be a lie about the material, showing flat faces where the real paper is quietly bending. So there are step diagrams instead, drawn from the sheet on the table, each one a position your hands can actually reach.
The Nine Hollows
The crease map holds forty creases meeting at twenty-one points. Nine of those points sit inside the sheet, away from any edge, and those nine are the hollows the name refers to — each one a small basin that forms when the surrounding paper commits. Eighteen creases stand up as mountains, six fall away as valleys, and sixteen run around the outside where the sheet ends.
The angles are simple and few: 71.6° and 108.4°, alternating around each interior meeting point. That pairing is what gives the finished surface its slightly leaning rhythm, neither square nor obviously diagonal. All nine interior points fold flat, which we checked point by point, and the angle spread sits well inside the window we require before a pattern goes out. The five standard checks passed; that is all they need to be said about here.
In the hand it is a firm thing. Push a finger into one basin and the neighbours resist, then give, then hold again. Damp paper takes the shape deeper. Thin paper takes it faster and loses it faster.
Which is why the children at the market keep pressing, long after the eggs are gone.