Tile completely this 47 x 47 square with rectangles. Each rectangle must contain precisely one numbered cell, and that number must be the area or perimeter of the rectangle it finds itself in.

so you can answer What are These?

$NINE$ + $5$ $EIGHT$ + $3$ $SEVEN$ + $2$ $???$ + $?$ $FIVE$ + $1$ $????$ + $?$ $?????$ -$?$ $???$ - $?$

During their holidays Martina, Karl and Jim played badminton every day. The winner of each match continues to play in the next match against the one who just had a break, while the loser of this match pauses. At the end of their holidays, it turned out that Martina played 18 matches, and ...

Cannot wrap my head around these 2, please also tell me what the logic is? For the 2nd one I think it might be a water droplet shape? But not sure about the logic. Thank you

A Sudoku's difficulty level is often the first thing readers notice about a puzzle. For questions and answers showing a puzzle it would be nice to have a relatively objective linkable tester. I've used Thonky.com's Sudoku Difficulty Estimator for this purpose, but according to user21820 it seem...

Unlock the lock with the key. You might want to put this next to a certain website's url. You know, the website where they post images and stuff? I think it was named after images or something. . . /a/8QemVeM Is enough said already? Complete the link. https://www.youtube.com/watch?v=hClK7Sn ...

User Abigail comments on the titling of "Do sudoku answers always have a single minimal clue set?" : I'd be surprised if there were a Sudoku which doesn't have at least 2 disjoint clue-sets. Well then, is there a Sudoku answer that has only a single minimal clue set?

The diagram below shows a partially-filled "octagram". Step into it, if you dare! At every vertex in a long word. Flowing into every vertex are two short words. Anagrammed together, these two short words yield the long word. Flowing out of every vertex are two more short words. Anagrammed...

In each cell of a 5 × 5 square there is a token that is black on one side and white on the other. Initially all tokens are placed with the white side facing up. On each move three tokens in consecutive cells in a row or in a column are flipped over. What is the smallest number of moves...

Here is a short sequence that I made when brainstorming puzzles: 19 101 920 20009 701 104 403 311 3000000000000000004 ... You need to figure the next one out. Just so you know, this is an actual series that I made, and although the jump to 3,000,000,000,000,000,004 is ridicul...

An architect wants to plan the creation of a house, but he has only two perspectives, one from the left and one from the front. The house consists of concrete cubes. All concrete cubes must be connected. How many cubes does the architect need to build the house at most? Perspectives, the l...

Since it seems at least some people are enjoying these I'm continuing the series. This one is not quite as elegant, but still interesting. Can White Castle?

I make billions, I never spend less than $1000, I'm a man in black, I'm a force of nature, I'm the original, Audiences of all ages have seen me. Who / what am I?