Puzzle kind · Ink
Ink: which layers does it soak?
A drop of ink lands on the folded stack and soaks through only the front two layers. Which squares of the sheet end up stained?
The rule
After the last fold, ink lands on one or two squares of the stack’s front face. It stains the front two layers at that spot and no more: the layers further back stay dry. Each drop sits on at least three layers, so the order of the layers decides the answer.
The front layer is the square you can see, and it never moves during folding. The layer behind it is the first piece of paper that was folded onto that square. Unfold, and the two stained squares are the front square and the one that was folded onto it.
How a round goes
- Fold the sheet following the diagrams.
- Ink lands on the folded stack, labelled INK SOAKS TWO LAYERS.
- On the flat sheet, mark every square you think is stained. Each mark shows as ink; touch it again to remove it.
- Press CHECK. The stained paper unfolds over your prediction: green found, orange dashed missed, red cross wrong.
Why the order matters
Folds do not just stack paper, they put it in an order. Two fold sequences that leave the same number of layers can put different squares directly behind the front layer. If you only count layers you will find the right number of stains in the wrong place, which is why ink puzzles are about which layer, not how many.
Tips
- Build the pile for the stained spot. List its layers front to back, then take the first two.
- The front square is always stained. Mark it first, then find its partner.
- Redo the folds in order, tracking which square lands directly behind the front one.
Where ink appears
Ink is introduced in level 17, after three straight folds, with one drop first and then two. It returns in level 19 with a flat sheet and diagrams only, and in Infinite Bloom.