Puzzle 81: Fell from the Sky

Skyscrapers Latin square: Put a number between 1 and 7 into each cell inclusive such that each row and column contains exactly one instance of each number. If we consider the numbers as heights of buildings, each number outside the grid tells the number of buildings visible from that point, looking into the grid. For example, an observer to the left of the sequence 1426375 sees four buildings (1,4,6,7; other buildings are hidden by taller buildings to the left).

Expected difficulty Medium • Answer • Comment/E-mail if you want a solution to be published

Puzzle 81: Fell from the Sky
Skyscrapers

This is the first in the series of the rejected puzzles for FAST, a joke test for April Fools Day. As described in a post in the discussion thread, my initial idea was “normal-sized” puzzles (even though I actually had 12×12’s and not 10×10’s), but with answer keys that are trivial to obtain. This, in some cases, lend to actually trivial puzzles too, but I don’t really like that, and hence here’s a handpicked collection of puzzles that I deem to be interesting enough even with the trivial answer key restriction. (Thus the title follows; the puzzles are those that “fell from the sky”, failed to be picked for the party.)

From The Archives 001: Symmetric–

This puzzle originally appeared in Deception, as the Bottom puzzle of Elimination Tapa.

Elimination Tapa Nurikabe-style: Shade some of the cells black. Black cells must be connected, but no 2×2 square may be all black. Cells containing numbers may not be shaded black. A cell with numbers represents the lengths of contiguous black cells in the cells adjacent to itself, separated by at least one white cell between different groups.

In addition, each square with numbers has one extra number. Removing extra numbers is part of the puzzle. Question marks indicate unknown numbers.

Expected difficulty Hard • Answer • Comment/E-mail if you want a solution to be published

From The Archives 001: Symmetric–
Elimination Tapa

Clearly intended to be a standalone post for this.

Yeah, reposting puzzles I’ve published somewhere else. This includes my old blog.

Also, yay, managed to disable anti-aliasing with a program!

Chess 4: How Is Castling Possible Again?

These chess problems require you to understand the rules of chess. Assume White is on the bottom.

Expected difficulty Medium • Comment/E-mail if you want a solution to be published

Stipulation (12+13) White can still castle. Which unit made White’s last move? (Note that you’re not told whose move it is.)

Here’s one more. Apparently constructing chess compositions is harder than constructing logic puzzles…

Puzzle 80: Hardcore Mode

Counting Count the number of paths from S (start) to G (goal) that stays along the white roads. Paths cannot use the same road twice but may visit the same intersection twice. As an example, the pink path shows one valid path.

Expected difficulty Insane • Answer • Comment/E-mail if you want a solution to be published

Puzzle 80: Hardcore Mode
Counting

Erm. You may use a calculator or a program. (If you managed to program the solution, then you deserve the answer. I’m not responsible if you miscalculate when you’re multiplying large numbers by hand.)

This is a rejected puzzle of a set born out of a stupid idea. Why did I even think of this? The good news is I have a free Brilliant.org problem idea, and I can practice my programming skills.

Chess 3: Weirdest Stipulation Ever

These chess problems require you to understand the rules of chess.

Expected difficulty Medium • Comment/E-mail if you want a solution to be published

Stipulations Color the pieces so that there exists a game where this position is illegal due to FIDE Chess Law 5.2b (also known as Dead Reckoning), but legal otherwise.

Made from phone, so it’s hard to add comments, but it’s basically a really stupid problem. I might put the solution soon. And I’m expecting a cook here, that there exists other solutions I didn’t consider or something. But if there’s none then, well, good.

Chess 2: Missing Piece

These chess problems require you to understand the rules of chess.

Expected difficulty Medium • Comment/E-mail if you want a solution to be published

Stipulations a) On what square was the rook on f1 at the beginning of the game? b) What color and piece is on h2 (the black circle)? Mention all pieces that can be on that square. (Just so part a is well-defined, I assure you at least one piece works.)

So here’s another one, which I should say is the best piece I’ve ever composed to date. (Yes, if this is the best piece then you know how beginner I am in compositions.) I might post some problems that aren’t composed by me, but I find interesting nevertheless…

Puzzle 79: Hidden Object

Expected difficulty Hard • For personal reasons, I decide not to release the answer/solution for this puzzle. Sorry 😦

Puzzle 79: Hidden Object
Nonogram
(click to enlarge)

Chess 1: A Long First Step

These chess problems require you to understand the rules of chess. Assume White is on the bottom.

Expected difficulty Easy • Comment/E-mail if you want a solution to be published

Stipulations a) Is the position legal? b) Move pawn f7 to g7; is the position legal?

EDIT: Puzzle edited on 7 February.

I call this Chess 0. 😛

Yes, with at least one positive feedback, I’m starting to post these. I’m also a relatively newcomer to the field, so my difficulty rating will be based on my current knowledge at the time of the posts. And don’t expect a lot of stuff, since constructing these is way harder than constructing the usual deductive logic puzzle content. Expect more retro chess problems (or perhaps helpmates and similar), those that don’t require thinking like chess players.

Also, I might consider adding a new difficulty rating “Introductory”, which should be self-explanatory. (Retro 0 is Introductory.)

Chess 0: Chess Problems Begin!

This blog is partially known by its puzzle content. But it’s still my creation, so I still post content according to what I like.

Lately I’m interested in retrograde analysis; that is, analyzing chess positions and problems that require looking to the past. Say, can you figure out the last move (precisely; the piece, the squares moved from and to, the piece captured if any, and any other stuff) from this position?

I’m interested on knowing how many of you like this kind of content. If there’s nobody, I might post my problems only on Chess.com, or something…just see. 😛

Puzzle 78: Totally Not An Approval

Scrabble Example

Scrabble Put some letters into the grid. The words that can be read (a span of two or more letters, preceded and followed by either the edge of the grid or a blank space) must be listed on the right, and no other word can be formed. All letters must form a single connected region.

Expected difficulty Easy • Answer • Comment/E-mail if you want a solution to be published

Puzzle 78: Totally Not An Approval
Scrabble

So Prasanna asked me to testsolve a Scrabble puzzle, with a word bank that resembles a sentence but has broken grammar. I suddenly got the idea for this word bank (which, Prasanna, has a perfect grammar, even if it uses a slang (v.intr. definition #4) 😛 ), and quickly whipped this puzzle in head. Turns out it’s unique, so why not. It’s actually Easy-Medium or something, as it’s not that trivial, but heck whatever.

Aftermath: Prasanna went hyper.

Also I went on to replace Puzzle 5; nobody noticed “the second path goes nowhere” and “the second path leads to freedom” are two contradictory statements?