The dry block is there to measure the wet one

Two book blocks, side by side, drawn square-on as flat elevations of fine vertical lines.

The left one is level: straight along the top, straight down the outer edge. The right one stands clearly taller, its top edge broken into a run of ripples, with a dead-straight horizontal line across the middle and everything below that line stained brown.

Water climbs to a height and stops. That is why the last straight line left in the damaged block is the one the water drew.

Why are there two blocks instead of just the wet one?

Because swelling is a quantity, and a quantity needs something beside it to be read against.

On its own, a cockled block is a shape — interesting, unmeasurable, and easy to dismiss as stylisation. Put a sound copy of the same object next to it, top edges starting from the same shelf, and the difference stops being decorative. You can see the surplus. That surplus is the whole subject, and the left-hand block is the instrument, not a companion piece.

Neither block carries lettering, which is deliberate. A title would give the eye somewhere else to go, and what is being shown is a thing that happened to paper rather than a thing anybody wrote.

What drew the straight line across it?

The level the water reached and held.

A block standing upright in shallow water takes it up from the foot, and it keeps rising through the fibre until the pull upward and the weight of the water balance. That height is flat because the surface of standing water is flat. Every other edge in the damaged block has since gone crooked; the line the water left has no reason to.

The colour underneath it reports something else. Paper carries substances that travel with water and gather at the point where the movement stops, so a boundary that has gone brown is a boundary that stood there for a while. A splash dries out and leaves a cockle with no line. This one sat.

Why does the top edge ripple when the bottom stays flat?

Because the sheets grew, and the only direction the extra length could go was up.

Paper takes up water, swells across the fibre, and does not return to the size it started at. Each sheet dries a fraction different from its neighbour. Clamped along the bound edge and pressed against a few hundred others, none of them can lie flat, so the surplus travels to the one free edge and buckles it. The foot stays flat because the foot was sitting on something.

That is also why the block stands taller. The added height is not one dramatic sheet; it is a small error repeated several hundred times and added up.

Whose permission does a soaked copy need?

Nobody's. What is drawn here is what water did to paper you own, and there is no title, author, publisher or classification anywhere in either block.

Covers, jackets and series designs do belong to somebody, and they are licensable like anything else — if a real one is the point of the design, getting that permission is part of the job. It is simply not the point here. The blocks are blank because the shape is the subject.

Style has no owner. A work does.

A drawn elevation of leaf-lines is a way of representing a thing, and nobody holds that. A specific cover is somebody's work. It is worth adding that the anonymous version is the stronger shirt: a recognisable jacket is one a great many people already own, while this particular amount of swelling happened once.

Can the same design be made from a different kind of damage?

Yes, wherever the damage arrived as a level, a boundary or a front rather than as general wear.

Sunlight on a shelf leaves a hard vertical division where the neighbouring volume shaded it. Heat curls a block toward one face. A crush leaves a crease running through every sheet at once. All of those give you the two things this design runs on: a boundary with a direction, and an undamaged part to hold it up against. A copy shaped by nothing more dramatic than being carried around in one hand works on the same comparison.

Isn't this just a picture of a ruined book?

No — the block is larger than it was and will stay that way, and neither of those facts stops it being read.

A swollen block holds its own leaves slightly apart, sits proud of its neighbours on a shelf and opens more easily than it used to. What it will not do is go back. That permanence is what makes it worth printing: the same conversion runs through a copy forced open at one page until it stays there, and through a paperback still in service under a stretched band. An object that has been through something and carried on is a different object, and the drawing is about the difference rather than about the accident.

Does it print well?

Yes, with one adjustment: the leaf-lines have to be drawn coarser and fewer than they are in life.

Ruled at the density of real paper edges they drop below what the weave can resolve and fill in to a flat grey, which loses the ripple at the top and the whole texture with it. Fewer lines, further apart, with a broken quality along each, keeps both. The stain works as one flat area of colour with a hard top edge — a soft fade across that boundary would go muddy and take the line with it.

Three inks at most: a dark outline, the line-field, and the brown. Dust blue is a good ground because it stands away from both paper tones; bone, oat and pale sage do the same job. The rectangles are the objects' own outlines rather than a frame drawn around the artwork, which is the difference between a diagram and a picture glued on.

How do I get one made?

Describe the copy at JustOG — how high the line sits, how much taller the block stands now, and what colour it dried. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.

Designs other people have published are in the shop.

It still shelves. It just takes more room than the copy beside it.