This puzzle is inspired and descended from this one: Brain-breaking 3D masyu Here the exact copy of rules, for convinience: This is a three-dimensional masyu puzzle.1 The five squares depict the layers of a $5\times5\times5$ cube. The goal is to make a single loop in 3D space which fulfills the following properties: The line passes through centres of cells and makes 90-degree turns only. The line cannot cross itself or branch off in multiple directions. The line passes through every white and black circle. When passing through a white circle, the line must go straight through the circled cel ..read more

FIND THE WORD HIDDEN IN THE IMAGE BELOW. GOOD LUCK ..read more

Another Venn based puzzle from me. The three overlapping ellipses form seven curved regions. Your task is to place exactly one tile per region, so that the four tiles in any one ellipse can solve the corresponding clue ..read more

What bird is represented below ..read more

This is a three-dimensional crossword. The seven grids below depict the layers of a 7x7x7 cube. "Across" and "down" clues work like in normal crosswords, and "away" clues go through the layers, using circled cells only. Solve on Penpa+ Across 1. John's hostesses discovered he's frequently almost fully nude (4) 4. Unfinished book describing everyday activities (3) 6. She met 5 down January 6th in Congress (4) 8. Eggs and avocado brought over (3) 10. Scratch middle of dark stone? (4) 12. Beyond the far edge of system, radiation reveals an orbiter (3) 13. Native American people had system of rel ..read more

Imagine a 2D plane, where each point represents a position. Your mission is to trace a path from the origin (0,0) to an end point (x,y) following a set of specific rules. Each step in the path can be one of four types: Up: Move one unit upwards. Down: Move one unit downwards. Left: Move one unit to the left. Right: Move one unit to the right. The path is defined by a sequence of these steps, and each step increases the total number of steps taken by 1. The "footprint" or "signature" of the path is represented by a unique value P, which corresponds to the cumulative sum of all steps. The Chal ..read more

This Colombian Sudoku is by Xavier Castillo. Usual Sudoku rules apply. Additionally, digits on each of the two diagonals must all be different. The dots outside the board above indicate how many cells in the corresponding column or row of that board contain precisely the same digit as is to be found in the same cell of the solved Sudoku below ..read more

I found this puzzle in a school study group. Choices are 9, 10,11, 12, 13. $$ \begin{array}{|c|c|c|c|} \hline 22& 22 & 23 & 24 \\ \hline 22 & 32& 41& 52\\ \hline 23 & 41 & 50 & 61\\ \hline x & 17 & 26& 37 \\ \hline \end{array} $$ I have tried so many operations on these numbers with many various arrangements. I think the 4th row is a result of first three rows ..read more

Can you tile a $25 \times 25$ square (no overlaps, no gaps) with a mixture of $2 \times 2$ squares and $3 \times 3$ squares? This puzzle is by David A. Klarner. Clarification: The number of $2 \times 2$ squares and $3 \times 3$ squares can be the same or different ..read more

Follow the ouroboros down valleys and over mountains. Is it even going anywhere? Interactive Penpa+ version ..read more