Over-Unfolding

One unfold too many

Every fold you undo mirrors the holes across a crease. The over-unfold trap is what happens when you undo a crease that was never there.

The generator builds it by taking your correct pattern and adding its own mirror image on top of itself — the pattern plus its reflection, kept together as one option. The result is the grid you would produce if the sheet had been folded once more along a midline and you dutifully unfolded that phantom fold as well.

Correct answer — 3 holes

Over-unfold — 4 holes

The correct answer here is three holes across the top. The trap keeps all three and adds the fourth position needed to make the row symmetric left to right. Nothing was moved. Something was added.

The generator constructs this trap two ways for every item, once against the vertical midline and once against the horizontal one, so the extra material can arrive from either direction:

Correct answer — 3 holes

Over-unfold — 6 holes

Same correct answer, mirrored downward instead of sideways: three holes become six. Over-unfolding across the horizontal midline doubles the pattern into the bottom of the sheet, where the paper in this item was never folded at all.

It is always bigger, and that is fatal

This is the one wrong-answer family you can kill without looking at a single position. An over-unfold option always shows strictly more holes than the correct answer.

The reason is airtight rather than statistical. A pattern combined with its own mirror image contains every hole of the original, so it can never be smaller — it is either strictly larger, or exactly equal. And it is exactly equal only when the answer was already symmetric about that midline, in which case the candidate is identical to the correct answer and the generator discards it as a duplicate rather than printing the same grid twice. Equal never ships. What ships is always larger.

So the check is simply: count the holes in the answer you derived, and refuse any option with more. Across roughly 18,000 generated wrong answers there is no exception — every over-unfold option that reaches an item exceeds the correct hole count. The family is worth the two seconds: it accounts for 10.4% of wrong answers on easy items, 18.5% on medium and 20.1% on hard.

The trap can get large. The generator refuses any option above twelve holes, and correct answers in this section top out at eight, so an option carrying nine or more holes is beyond anything the folds can produce.

Symmetry is evidence of nothing

Over-unfolds are seductive because they look resolved. A pattern balanced about a midline feels like the product of clean folding, while your own derived answer — three holes bunched to one side, a run that stops short of the edge — feels unfinished. That instinct is backwards.

A symmetric option is not more likely to be correct. Correct answers in this section are asymmetric about the vertical midline in 58.1% of easy items, 71.3% of medium items and 72.1% of hard items. On a hard item, the lopsided-looking grid is the favorite. Neatness is a property the trap was manufactured to have, and your answer was not.

Which means the pull you feel toward the tidy option is information about the option's construction, not about the paper. Derive your hole count, then let the count decide.

Try it on a live item

Work the item below and settle on a hole count before you look at the options. The item's own explanation states how many holes the punch produces, so you can check yourself — and then check how many of the five options that number alone disqualifies.

The paper is folded as shown, then punched through all layers. Which pattern shows the holes on the fully unfolded sheet?

A

B

C

D

E

3 folds, then 1 punch through 6 layers — 6 holes appear when unfolded. Unfold in reverse order: each fold mirrors its holes across the crease.

More of them are waiting in the hole punching practice generator.

The takeaway

The over-unfold trap is your answer plus its own mirror image, the grid you would get by unfolding a crease the sheet never had. Because it keeps every hole you found and adds more, it always shows a strictly larger hole count than the correct answer — the one family a pure count check destroys on sight. It survives on the page because it looks balanced and finished, but symmetry is not evidence: most correct answers in this section are not symmetric at all.