Puzzle #25 – Doppelblock (USPC ’19)

Theme: Today’s Puzzle

Standard Doppelblock rules.

Hi all, I’m just writing to share the news that one of my puzzles was featured on this year’s US Puzzle Championship (which took place July 20, 2019)! In case some would like to try the USPC in full on their own, I’ve refrained from posting the image directly; instead, the relevant page of the test PDF is here. The rules for the puzzle are also described in full in the attachment.

My many thanks to Nick Baxter for contacting me with an offer to contribute to the test! I was somewhat hesitant, but I anticipated based on my summer plans that I wouldn’t have time for the USPC this year, so I agreed to contribute. I’m torn between contributing and participating next year, but I guess that’s a decision to be left for later.

Puzzle #19 – Snake

Theme: Multiples of 3

Rules: Draw a “snake” (a 1 cell-wide path) in the grid. The snake cannot touch itself, not even diagonally. (That is, if two edge-adjacent cells are part of the snake, they must be consecutive cells in the snake, and if two diagonally adjacent cells are part of the snake, there must be exactly one cell between them in the snake.) The two ends of the snake are given (so the snake must contain exactly 45 cells). Each clue outside the grid gives the number of cells in the corresponding row or column that are part of the snake.


Puzzle #18 – Easy As… (Fuzuli)

Here’s another type that appears on the Grand Prix round; I can’t find many other instances of this particular variation (there are a couple online).

Rules: Place letters from the given list into some cells (at most one letter per cell) such that each letter appears exactly once in each row and column, but no 2×2 group of cells is entirely filled with letters. Some cells may already be filled in for you. Additionally, each letter outside the grid indicates the first letter that appears in the corresponding row or column in the corresponding direction.


Good luck to all those taking the test this weekend!

Puzzle #17 – Binary Parquet

This is a puzzle I recently constructed as practice for the upcoming Polish round of the 2019 Puzzle Grand Prix. The type seems to be completely new (at least, a Google search for the exact name turns up no results…).

Rules: Shade some of the cells in the grid black, leaving the rest white, such that no two 2×2 squares have the exact same shading. Each clue outside the grid indicates the length of the longest consecutive group of cells of the specified color (black for the outer clues, white for the inner clues) in the corresponding row or column.


For ease of solving, here is the set of all 16 possible 2×2 squares (so each must be used exactly once).