# Seven similar 7x7 (pen-and-paper) logic puzzles

Oh no! I've just finished drafting some 7x7 logic puzzles, but I accidentally dropped all of them on the floor, and now they're all mixed up!

To make matters worse, I haven't gotten around to polishing their visuals yet, so they all look the same and I can't tell any of them apart! Some numbers are even written sloppily to the point of illegibility, marked by question marks.

Oh, kind puzzler who just conveniently happen to be passing by, would you help me identify which grid is which puzzle type, and solve them for me? I would be very grateful!

I remember making seven puzzles, each one being one of these seven different types:

• Akari : Place light bulbs in some unshaded cells, such that every unshaded cells is lighted by a bulb, and no two lightbulb light each other. Lightbulbs shoot a ray of light in all four direction until it hits either the border of the grid, or a shaded cell. Treat all non-empty cells as shaded.

• Choco Banana : Shade some cells in the grid to form regions of shaded and unshaded cells, such that every shaded region is rectangular, and every unshaded region is NOT rectangular. Squares are rectangles too. If a region contains a number, the size of that region must equal that number. Regions may contain multiple copies of the same number, or no number at all.

• Fillomino : Divide the grid into regions, such that no two regions of the same size shares an edge. If a region contains a clue number, the size of the region must equal that number. Regions may contain multiple copies of the same number, or no number at all.

• Minesweeper : Place mines into some non-clue cells. Clue cells indicate the number of mines within the 8 neighbouring cells (orthogonally and diagonally adjacent).

• Nurikabe : Shade some non-clue cells to form unshaded regions, such that every region contains exactly one number, which equals to the size of that region, and the shaded cells form a big region. There may not be any 2x2 block of shaded cells.

• Shikaku : Divide the grid into rectangular regions, such that every region contains exactly one clue cell, which equals to the size of that region.

• Slitherlink : Draw a singular loop along the edge of the cells that does not branch off or cross itself. Clue cells indicate how many of its four borders is part of the loop.

Sorry if my explanation aren't the clearest, you can use the link provided to see an example puzzle.

Thankfully it's not just 100% guess-and-check, there are some clues and observations you can use to identify the puzzles easier, and every individual puzzle is has a singular unique solution that is reachable without guessing.

If you need a starting point, here's a hint in case you need them:

Consider which genres has elements that are not allowed in other genres. For example, how many of the seven genres cannot have 0 as a valid clue cell?

• So, to be clear, all 1s in Choco Banana are shaded, right? Commented Aug 31, 2023 at 0:39
• @newQOpenWid that is indeed a consequence of the ruleset Commented Aug 31, 2023 at 11:32
• The question marks are never mentioned in the question. For clarity, what are they? There must be a number there but unknown? Or can it possibly be empty? Commented Sep 7, 2023 at 4:38
• @justhalf Technically it depends on which genre the grid is in, but yes you can treat all of them as an unknown number. Commented Sep 8, 2023 at 17:09

The only puzzle grids that don't have 4s (which are not allowed in Slitherlink) are grids 1 and 6. 1 has too little clues, and we know every puzzle has a unique solution, so puzzle 6 must be a slitherlink.

Due to the number of 3s in the grid, the slitherlink can be easily solvable and the question marks filled in (they are all 0's and 2's):

Now,

Two grids have 0's. Puzzle 6 is the slitherlink grid, so the other, puzzle 1, must be either Akari or Minesweeper because only they can have zeros. If it is Minesweeper than there are multiple solutions, so it must be Akari. Now we assume the question marks should be shaded.

We can solve the Akari by noting the forced placements of bulbs in the corners.

We can now make intutive deductions about which puzzle is which. Two adjacent clues are contradictory to Nurikabe's rules, so Nurikabe puzzles have to be puzzles 2, 3 or 5. Puzzle 5 at first looks like it might be solvable as a Nurikabe. However, the diagonally adjacent 2 and 4 as well as the 1s force the creation of a pool. Similarly the 3-1 combo in the bottom left corner of puzzle 2 forces a contradiction. Then puzzle 3 must be Nurikabe (thanks for the OP for bringing up the question marks!).

The corner 3-1 configuration in puzzle 2 and the corner 4s in puzzles 4 and 7 make them impossible for Minesweeper. Puzzle 4 is Minesweeper.

Shikaku is number 2 (number 7 has multiple solutions, and double-checking, this puzzle has only one).

Now we have either Choco Banana or Fillomino for puzzles 4 and 7.

Solving puzzle 7 as a Choco Banana gives us this:

Then,

We solve the last puzzle, puzzle 4, as a Fillomino (contradiction fixed by OP), getting

This was a great idea for a puzzle and definitely made me think!

• Hello! Thank you for giving this set of puzzle a go, (rot13) V nz noyr gb pbasvez gung sbhe bhg bs svir nffvtazragf urer vf pbeerpg, juvyr guerr bs gur svir tevq lbh cbfgrq ner pbeerpg. n) Vg frrzf Nxnev'f "gerng ?f nf funqrq" pnyhfr nppvqragnyyl tbg pneevrq bire gb Ahevxnor fb gurl raqrq hc zvffvat, naq o) lbhe Fuvxnxh vf npghnyyl abg havdhr, nf lbh pna znxr na nygreangr fbyhgvba ol gheavat gur e4p3 4 pyhr vagb n iregvny 4 ertvba. Commented Aug 28, 2023 at 4:42
• @KusaneHexaku I believe I have fixed the Shikaku and Choco Banana. But I run into ap roblem with the fillomino. Commented Sep 2, 2023 at 21:49
• Hi again! Sorry for the late reply. (rot13) Gur ernfba lbh eha vagb na vffhr jvgu gur 2 vf orpnhfr bar bs lbhe nffhzcgvba nobhg gur 3f ner snhygl. Purpx ntnva gb frr juvpu bar vfa'g npghnyyl nf sbeprq nf lbh guvax vg vf. Commented Sep 6, 2023 at 17:49
• @KusaneHexaku Oops! I didn't even notice the rot13(ubevmbagny bcgvba sbe gur e4p4 3) Commented Sep 6, 2023 at 22:44