Numberlink Cover is Quirk's version of Numberlink, a puzzle also called Arukone or Number Link.
The classic puzzle joins pairs of numbers. Quirk uses pairs of letters, as Arukone does.
In Quirk, filling every open box is always part of the rules. That is why the puzzle is called Cover.
The rules
- Draw a line to join each pair of matching letters.
- A line goes sideways or up and down, from box to box. It never goes corner to corner.
- Lines can't cross or share a box, and together they must fill every box that isn't crossed out.
- A line can't split, make a loop, or go through another pair's letter.
- Crossed-out boxes are not part of the puzzle. No line goes through them.
Some classic Numberlink puzzles do not ask you to fill every box. In Numberlink Cover, an empty open box always means the puzzle is not done yet.
A worked example
The first board has 2 rows of 3 boxes. The boxes are numbered 1 to 6, row by row.
| Column 1 | Column 2 | Column 3 | |
|---|---|---|---|
| Row 1 | Box 1: A | Box 2: A | Box 3: B |
| Row 2 | Box 4: empty | Box 5: empty | Box 6: B |
- The two A letters sit next to each other. A short line from box 1 to box 2 looks easy, but wait.
- Look at the B in box 3. It is next to box 2 and box 6.
- Box 2 holds an A, so B can't go there. B must go straight down to box 6.
- Now boxes 4 and 5 are still empty. B is finished, so only A can fill them.
- Draw A from box 1 down to box 4, right to box 5, and up to box 2.
- Every box now has a line, and no lines cross. The puzzle is solved.
The second board has 2 rows of 5 boxes. Box 8 is crossed out.
| Column 1 | Column 2 | Column 3 | Column 4 | Column 5 | |
|---|---|---|---|---|---|
| Row 1 | Box 1: A | Box 2: empty | Box 3: empty | Box 4: empty | Box 5: A |
| Row 2 | Box 6: B | Box 7: B | Box 8: crossed out | Box 9: C | Box 10: C |
- Look at box 3 in the middle. Box 8 below it is crossed out.
- So box 3 has only two open boxes next to it: box 2 and box 4.
- Box 3 has no letter, so a line must come in from one side and leave from the other.
- That line joins the left part of the board to the right part.
- Only pair A has one letter on each side. So the line through box 3 belongs to A.
- Draw A through boxes 1, 2, 3, 4 and 5.
- Join B from box 6 to box 7, and C from box 9 to box 10. Every open box is filled.
Beginner techniques
Only one way out
A letter needs exactly 1 line. If a letter has only one open box next to it, the line must go there.
Treat other pairs' letters and crossed-out boxes as walls. They often leave a letter just one way out.
Empty boxes need two ways in
A box without a letter needs 2 lines: one in and one out. If it has only two open boxes next to it, use both.
Boxes in corners and narrow spots are a good place to look first.
Take the longer way round
Two matching letters next to each other may not want the shortest line. Sometimes their line must curve to fill empty boxes nearby.
Ask which pair is able to reach an empty box. If only one pair can, its line goes through that box.
One gap between two areas
Look for two parts of the board joined by just one gap. Only a pair with a letter on each side can use that gap.
Any other line would have to pass through the gap twice, and that is not possible.
Rule lines out
When you know a pair can't use a line between two boxes, rule it out with a note. This keeps your thinking clear on bigger boards.
Common mistakes
- Joining two nearby letters with the shortest line and leaving boxes empty.
- Running a line through a letter that belongs to another pair.
- Shutting in an empty box so it has only one open box next to it. No line can fill it then.
- Drawing a line into a crossed-out box. Those boxes are never used.
- Thinking you are done once every pair is joined. Every open box must also have a line.
Questions
Is Numberlink Cover the same as Numberlink?
It is very close. Quirk uses letters instead of numbers, and filling every open box is always a rule.
Is it like Flow Free?
Yes, the idea is the same. Flow Free uses coloured dots, and its rules also ask you to fill the whole board.
Is it the same as LinkedIn's Zip?
No. In LinkedIn's Zip you draw one single line through numbers in order. In Numberlink Cover, each pair of letters gets its own line.
Does every puzzle have one solution?
Yes. Each board has exactly one way to join all the pairs and fill every open box.
What sizes are there?
Boards in Quirk go from 3 by 3 up to 6 by 6. Bigger boards have more pairs, and some boxes may be crossed out.
What can I do when I am stuck?
Ask for a hint. It points to a spot on the board and explains which line must go there. You can also undo moves or reset the board.
Related puzzles
Playing it in Quirk
Tap a letter, then drag or tap box by box to draw its line. To erase, go back the same way.
Open Lines and notes to draw, erase or rule out lines for the pair you chose. Undo and Reset keep the same board, whichever letter you start from.
