Rodolfo Kurchan created a wonderful new grid puzzle called One Up that you can play on his website. There is one main rule: Each horizontal and vertical sequence of N cells between walls, must contain every number between 1 and N, in some order. Can you construct an empty 8x8 One Up puzzle that has a single unique solution and it is connected - each empty cells can reach every other empty cell? No computers allowed. Bonus: can you find a method for constructing such puzzles for any grid size ..read more

This is part 63 of the puzzle series Around the World in Many Days. Each part is solvable on its own. Dear Puzzling, This is a sudoku deconstruction puzzle. Draw eight non-overlapping rectangular regions of size 2x4 (two rows of four cells each) into the grid. Each region contains the same eight letters once each and no letter is repeated in any row or column. Numbered cages in the grid contain, in normal reading order, answers to the clues below. The two numberless cages are simply there to help you find the final answer. Letters may repeat inside cages, if permitted by other rules. Cells wit ..read more

Background: As part of the entertainment at my brother's wedding - which took place in the UK on May the 4th this week - I created a puzzle hunt 'for a general audience' and a range of ages to fit with the day's Star Wars theme. The following 9 sub-puzzles were dotted about the wedding venue, each accompanied by an optional hint and a set of basic instructions (both accessed by lifting a flap, so that those who wished to engage in the hunt in the traditional instruction-less manner would be able to do so). The prize for solving? A free drink of Blue Milk from the bar! With the groom's permissi ..read more

You are given a grid. Some of the cells in the grid are labelled with positive numbers. You must partition the grid into triangles. There must be a triangle for each labelled cell Each cell must be completely contained within its triangle The vertices of each triangle must be intersection points of the grid Every triangle has one (or more) edges that are either horizontal or vertical The cell's label specifies the area of its triangle Here is an example to illustrate the problem. Observe that the restriction that every triangle must have a horizontal or vertical edge means that it is easy t ..read more

Puzzle I composed, the reasoning matters more than the correct answer ..read more

A positive integer is said to be an Ecuadorian number if for some m, the sum of the first m of its n digits, m < n, is equal to the sum of all its other digits. Numbers such as 11, 134, 235, 2024 are all Ecuadorian. What is the largest gap there can be between two consecutive Ecuadorian numbers ..read more

Inspired by question 126115 Make the three products equal and as large as possible in case someone or 126115 author feels this is plagiarism, be kind and feel free to close Assign natural numbers $1 2 3 4 5 6 8 9$ (note $7$ is missing) to points $A...G,H...N$ and find different remaining $6$ of total $14$ natural numbers to make all $7$ products of heptagon sides $AHB...GNA$ (listed counter clock wise starting from bottom) equal. What is the minimal common product ? bonus extra challenge: try to keep the natural numbers small ..read more

Try to make the numbers 1 - 100 using digits 2, 0, 2, 4 only ONCE. What you're allowed: Basic Operations (+ - * /) Square & Square Roots (Squaring uses a 2) Brackets & Concatenation (e.g. 20-(2+4)) Any kind of Factorials (!, !!) However, the modulus operator and rounding are NOT allowed. Good luck ..read more

What phrase is hidden below? 3 ? 5 ?? 8 ?? 7 ?? 20 ?? 12 ?? 9 ?? 28 ?? 11 ?? 16 ?? 33 ?? 48 ?? 13 ?? 36 ..read more

The 3Doku is a Sudoku-like puzzle with blocks of 4×4 cells on the faces of a cube. Instead of columns and rows, it has bands of cells that loop around the cube. It has me wondering how many essentially different solutions there are for a 3Doku. Essentially Different Solutions We can number the first block of an n×n sudoku from 1 to n², so 1 to 9 for a regular sudoku. All solutions we can find for that are essentially the same as when we swap the 2 and the 4. We get the same solutions, but just with the 2 and the 4 swapped. Other possible permutations are swapping entire columns or rows ..read more