How to Shorten an Internal Fold That Keeps a Paper Tile from Lying Flat

Start by placing the tile on a smooth, flat surface with its decorative face upward. Look along the edge to locate the raised area. Then turn it over and open only the flap nearest that area. Keep the surrounding folds recognizable so you can put the layers back in the same order.

Close the tile slowly while watching the hidden flap. Does its free end hit an opposing edge before the face settles? Does it bunch against the bottom of a pocket? Or does the tile lift even when that flap is outside the pocket? These observations determine whether shortening is a useful next step.

There is a documented reason to check clearance: designer Michał Kosmulski advises leaving a tiny margin between flaps when folding his Building Block Units from thick paper, rather than making the flaps touch exactly. The margin accommodates paper thickness. That supports testing for crowded edges, although it does not establish that every raised tile has the same cause. BBU unit family A: plain

Use this decision table before adding a crease. It is a practical troubleshooting aid derived from that clearance principle and the fold structures described below.

What you observe	What to try first
A free internal tip hits another edge, and releasing it lets the face settle	Test a small fold back at the tip
The flap sits diagonally in its pocket	Reopen and reseat it along the intended alignment
A ridge remains after the suspected flap is released	Inspect the underlying folds before shortening anything
The troublesome crease continues into neighboring shapes	Restore the documented folding sequence
The face lies evenly but has a raised stack of layers	Check whether that thickness is part of the design

A free flap has an accessible end that can be lifted without pulling another part of the tile out of alignment. That gives you somewhere to make a small adjustment. Here, “shorten” means reducing how far the folded flap reaches into its available space.

A connected crease is different. In a tessellation, pleats link twisted shapes across the sheet. Madonna Yoder’s introductory maker guidance explains that the twists, their connections, and the spacing between them define the pattern. Moving one of those creases independently can therefore change more than the troublesome spot. Use the original pattern to resolve that situation. How to Start Folding Origami Tessellations

Do not assume that stopping pressure halfway along a crease will shorten the underlying flap. First identify the actual collision: the free end, a side edge, or a folded junction. The tip adjustment below addresses excess reach at a free end. It will not correct a flap that is too wide for its pocket.

Keep the original diagram or tutorial nearby if you have one. Before opening the tile further, note which flap lies above the other and which edge serves as the alignment reference. A quick pencil sketch on separate paper can preserve that information.

You need a flat working surface and, optionally, a ruler for comparing the flap’s reach with the space available. A bone folder can help finish an established crease; Yoder recommends a bone folder or similar tool for making tessellation creases clear and easy to manipulate. Save firm creasing for after the adjustment passes its fit test. How to Start Folding Origami Tessellations

If the construction is difficult to reopen, reproduce the relevant flap and pocket on spare paper first. Match the original paper and dimensions as closely as practical. The useful test is whether the altered flap still closes and connects as intended.

The following sequence is an adaptation for a free hidden flap. It applies the documented principle of allowing clearance between crowded flaps; the exact adjustment must be established on your tile.

1. Expose the obstruction. Lift the covering layer until you can see the free end and the edge it contacts. Avoid flattening unrelated folds.
2. Find the available space. Hold the visible face in its intended position without forcing it down. Observe how much of the hidden tip extends into the obstructing edge.
3. Turn back a small amount. Fold the free end toward the body of its own flap, leaving the turned portion inside the tile. For a straight end meeting a straight obstruction, begin with a fold parallel to that end.
4. Make a light trial crease. Use only enough pressure to hold the adjustment during testing.
5. Restore the layer order. Return the flap to its pocket or position, following the original sequence.
6. Release and inspect. Remove your fingers completely. Check the face, the underside, and the connecting edges before deciding whether to crease firmly.

For an illustrative trial, you might turn back about half a millimeter on a small flap. This is a starting experiment, not a standard allowance. If the tip still catches, reopen and increase the adjustment slightly. If the added folded layer creates a new bump, reopen it and use the next section to choose another approach.

The endpoint of the repair is enough clearance for the tile to close naturally. A large fold back can consume more of a useful tab and place additional layers inside the pocket. Keep checking both fit and connection rather than judging only the top surface.

A return fold leaves the paper attached and adds a folded layer at the tip. If the pocket is already crowded through its thickness, that may be an unsuitable tradeoff. Another possibility is to refold the flap using its intended edge alignment, correcting an earlier inaccurate crease.

Repositioning is appropriate only when you understand the construction. Kosmulski’s plain BBU instructions, for example, use one folded edge to locate the opposite fold and specify a relationship between flap lengths and the unit’s body. That is a reminder to preserve the design’s references while adjusting clearance. It is not a general instruction to move every internal crease inward. BBU unit family A: plain

Likewise, a pleat contains opposing folds: Origami Guide demonstrates folding the paper one way and then folding a flap back with a gap. If your troublesome internal fold belongs to such a pair, inspect both folds and their spacing before changing either one. A misplaced return fold may be the issue. How to do Pleat & Crimp Folds

If moving the original fold changes the tile’s visible size, shifts a corner, or distorts its pocket, restore it. Reopen the preceding construction step or remake the unit with the intended alignments and a modest clearance where the designer permits one.

Test the repaired tile loose before inserting it into a larger arrangement. Set it down, release it, and look across the face at table height. Then turn it over and check that the shortened flap remains contained rather than slipping out of its pocket.

Use three practical checks:

• Face: Does the previously raised area settle without continuous finger pressure?
• Outline: Do the corners and edges still match the intended tile shape?
• Connection: Does the adjusted tab still engage its pocket or neighboring unit adequately?

For a tile with a repeated or symmetrical construction, compare the altered area with its counterpart. A newly uneven outline suggests that the adjustment has affected more than the hidden clearance.

Judge flatness against the model’s intended surface. Origami Resource Center explains that flat tessellations can still have raised ridges where multiple paper layers overlap. A stable layered ridge is therefore different from a face that arches because an internal tip is catching. Origami Tessellations

Once the tile closes, retains its outline, and connects properly, reopen just enough to sharpen the successful adjustment. Restore the layers and repeat the loose tabletop test. If the tile lifts again, check whether the flap has returned to the old crease or entered the pocket at an angle before making another alteration.

A useful repair removes a specific obstruction with a small, observable change. Find the contact point, adjust an accessible free end, and test the whole tile after each change. When the troublesome fold is part of a connected structure, return to the pattern’s geometry and folding sequence to resolve it.

• BBU unit family A: plain — Origami by Michał Kosmulski
• How to Start Folding Origami Tessellations — Gathering Folds
• How to do Pleat & Crimp Folds — Origami Guide
• Origami Tessellations — Origami Resource Center