Generator

The paper had to arrive first — the paper thinness generator

A generator in the who found it, and when library, called 42 times across 9 essays. Below: what it draws with nothing specified and with the settings the essays give it, what it checked while drawing, and everywhere it is used.

paper-thinness is one function. Everything below was drawn by it when the site was last published, at settings taken from the essays rather than invented for this page — so a figure here is the same figure a reader meets in an essay, and when the generator changes, this page changes with it.

With nothing specified

The paper had to arrive firstStack thickness is the layer count times the sheet thickness, and a fold stops working when the stack approaches the smallest feature being folded. So the number of layers a design can reach is fixed by the paper rather than by the folder — and the complex tradition is downstream of paper thin enough to carry it.a fold stops working when the stack reaches 3 mm8 layers16 layers32 layers64 layers128 layersnewsprint65 µm520 µm1.0 mm2.1 mm4.2 mm8.3 mmcopier paper100 µm800 µm1.6 mm3.2 mm6.4 mm12.8 mmkami70 µm560 µm1.1 mm2.2 mm4.5 mm9.0 mmwashi40 µm320 µm640 µm1.3 mm2.6 mm5.1 mmfoil-backed tissue26 µm208 µm416 µm832 µm1.7 mm3.3 mmunryu tissue18 µm144 µm288 µm576 µm1.2 mm2.3 mmthickness measured across the sheet; the smallest feature is a folder's working figurerather than a constant of nature

view: "substrate", show: "levels"

How deep each folded footprint is, point by pointFor every printed pattern, folded, the share of its footprint at each depth, laid end to end from the shallowest on the left to the deepest on the right, with the deepest depth and its share printed. Most patterns reach their deepest over a broad part of the footprint; two reach it only on a sliver.the share of each folded footprint at every depth, shallowest firsteach block is one depth, its length the share of the footprint that deep; the shading cycles so neighbours differThe preliminary base8 deep on 99.8%The Miura fold16 deep on 11.7%The square twist9 deep on 17.4%The hexagon twist7 deep on 24.4%The Yoshimura pattern60 deep on 100.0%Fold and cut — the triangle7 deep on 2.91%The tapered corrugation16 deep on 0.78%The waterbomb tessellation32 deep on 98.1%the tick marks where the deepest depth begins

view: "substrate", show: "tolerate"

What a proud hundredth buysFor every printed pattern: its deepest layer count and mean depth, the depth a bound must hold if it lets half a per cent, one, two, five and ten per cent of the folded footprint stand proud of it, and how far a one-per-cent tolerance moves the size at which the pattern uses its sheet and its paper equally.the depth a bound must hold if it lets a share of the footprint stand proudeach column: the least depth exceeded on no more than that share of the folded footprintpatterndeepestmean0.5% proud1% proud2% proud5% proud10% proudcorner, mm: none → 1%The preliminary base87.9988888134 → 134The Miura fold169.231616161616177 → 177The square twist93.0299999232 → 232The hexagon twist73.2577777197 → 197The Yoshimura pattern6060.006060606060134 → 134Fold and cut — the triangle71.1977711326 → 326The tapered corrugation168.331612121212186 → 161The waterbomb tessellation3231.483232323232135 → 135the corner is the finished size at which a design uses its 1200 mm sheet and a paper at the crease floor equally

view: "substrate", show: "curve", tol: 0.01

A tolerance does nothing until it passes the deepest shareFor every printed pattern, the depth a bound must hold as a share of the pattern's deepest point, against the share of the folded footprint the bound lets stand proud, on a logarithmic scale from a tenth of a per cent to thirty. Each curve stays at one until the tolerance passes the share of footprint at the deepest depth, then steps down; the marker is the tolerance chosen.the depth to be held, as a share of the deepest, against the share of footprint allowed proudeach line is one printed pattern; the upright line is the tolerance chosen00.2500.5000.7501-3-2-1-0.523share of the footprint allowed to stand prouddepth held, over the deepestthe preliminary basethe yoshimura patternthe waterbomb tessellationthe miura foldthe tapered corrugationthe hexagon twistthe square twistfold and cut — the triangleshaded label: a pattern whose deepest depth covers under a tenth of its footprint

What it checked while it drew

Collected while it drew, not written by hand. The count is how many separate times that claim was put to the test.

Where it is called

Every figure listed here is drawn by the same rule, so a mistake in the rule would be in all of them at once, and so would a correction.

A proud hundredth buys almost nothing

A folded design's sheet is set by its mean layer count and its paper by its deepest point, and the ratio of the two moved the size at which a design uses both equally. That ratio is two numbers of a distribution. Read the whole distribution of every printed pattern's folded footprint and the shelf splits in two: six patterns reach their deepest depth over at least a tenth of the footprint, and two reach it only on a sliver — the fold-and-cut triangle on 2.9 per cent, the tapered corrugation on 0.78. A bound that lets part of the footprint stand proud of the stack's ceiling does nothing at all until the proud share passes the deepest depth's share, so a hundredth moves one pattern of eight, and a twentieth moves two.

A sheet has a size as well

The layer count a design reaches is fixed by how thin the paper is. What size the finished thing comes out at is fixed by how large the sheet is, through a factor the pattern decides: the folded footprint times the mean layer count is the area of the paper, so the linear shrink is the square root of the layer count and a sixty-four-layer model finished at a hand's width wants more than a metre of sheet.

A sheet is as large as two arms

A model's finished size is its sheet divided by the square root of its layer count, so a sixty-four-layer model at a hand's width wants more than a metre of paper. A hand-made sheet is formed on a mould somebody lifts out of a vat and shakes, and what that bounds is an area rather than a thickness: over the whole plausible range of mould weights and what arms can do repeatedly, the largest square sheet runs from about half a metre to about two. The demand and the bound are the same sizes, which is the one thing about them nobody has to know the constants to see.

Closer than a crease is wide

One fold from a bare square leaves nine marks, seventy-five millimetres apart. Two folds leave five hundred and sixty-five, the closest pair half a millimetre apart. Three folds — using one axiom of the seven — leave half a million, and ninety-four per cent of them have another mark within a fifth of a millimetre. What bounds a folder is not what the axioms reach; it is what the paper can tell apart.

Eighty layers and the sheet decides the rest

Five of these essays each bound one thing and none of them bounds a design. Put together they close. The crease floor fixes the thinnest usable paper at about a fibre and a half; that paper's stack runs out at eighty layers; the largest sheet two arms can make falls away as the square of the finished size. The region under both is every model anybody can fold, and it has a ceiling at eighty layers and a corner at about a hand's width — above which the paper is no longer the limit and the vat is.

The deepest point pays for the paper

A folded design uses its sheet according to its mean layer count and its paper according to its deepest point, and the ratio of the two is a property of the crease pattern. Measured on every printed pattern it runs from exactly one to nearly six — and it does not split tessellations from bases, as expected. It splits patterns whose every panel lies over every point from patterns that keep a footprint with structure in it. The ratio moves the corner of the substrate map by its square root, so the fold-and-cut triangle can reach the paper's eighty layers at 326 millimetres where the preliminary base must stop at 134.

The paper had to arrive first

A model with sixty-four layers at its thickest point, folded in ordinary copier paper, is six and a half millimetres of stack. The layer count a design can reach is fixed by the substrate, not by the folder — so the elaborate tradition is downstream of a manufacturing achievement with its own dates.

The paper that will not hold a crease

Every constraint these essays have found improves as the paper gets thinner: the stack, the size, the layer count. A crease does not. A crease is a plastic hinge in the fibres at the fold, and a sheet one fibre thick has nothing through its thickness to hinge — so there is a floor under the thickness that no manufacturing skill moves, because the fibre diameter is a constant of the plant. The papers a tradition folds sit between one and a half fibres and four, and the two below that in this collection's own shelf are tissues, which are backed with foil before anybody creases them.

Which ceiling is binding

Two constraints hold a design's layer count down and both are ceilings on the same number. The stack gets better as the paper thins; the grid gets better as the sheet grows, because piling layers needs divisions and a division cannot be finer than a folder can place it. They cross at a sheet size that rises as the paper thins — so on the papers a classical folder had, the substrate really is the limit, and only at tissue weights does the hand take over.

All the figures · The who found it, and when field · The patterns a reader can fold