I met a man once while out for a walk. "Tut, tut!" He would say, as he wandered this way and that. I saw him approach a group, "You there! Will you trade? I've got a lovely a nut right here. What about you? A nut for a jar of tuna?" I didn't think this question was sincere, because I noticed that...

I found this paper which I think has a clue I need, but part's been torn off, and I don't recognize these words. Some of them don't even seem like words, just sets of characters. I'm sure there's a pattern though, maybe even more than one. What does it mean?

We have been through a lot with Dave. Lately, he is a bit strange. He always looks like he's trying to tell me something -- maybe some sort of confession. Today he sent me these maps. I know that those are the maps of Brazil, France, Australia, Turkey, Sweden, Brazil (again), Germany, and Holland...

Disclaimer: I'm embarrasingly inept with search engines, so please don't kill me if the following is a dupe or well-known fact (or super-hard open problem for that matter). Consider a domino tiling of a plane rectangle of size $n \times m$. (Obviously, at least one of $m$ and $n$ has to be even f...

You wake up in a world with an infinite blackboard and hear a voice. "Let's play a little game. In front of you is a infinite blackboard. You may create a new number by adding a power of $2$ to an existing number, or taking two preexisting numbers $a, b$ and writing down $a \mod b.$ If you wish t...

This post is not a puzzle. There is nothing puzzly hidden inside it or the self-answer, posted at the same time. No main body. See question(s) below. Question 1: What exactly is a connect-wall puzzle, and how do I write one? No lateral-thinking needed! Question 2: What exactly is a word-web p...

Up until a few months ago I was happily solving my 4x4x4 cube, then, thanks to a medical thing, I've lost/forgotten a few algorithms. I've got all of them back except 1, rotating the last 3 edges. What I remember is this: Everything is oriented correctly and the corners are positioned correctly....

Here is a riddle from my side. I think it's bit easy. Clues 8 times a day. Bent 97 of the cent useless. It saves you from death but you can also die within it. Might cause a war.

My brother Yzarc recently returned from his summer road trip, so I went to visit him. He seemed unusually quiet, sitting pensive in a chair and watching the clouds. This was unusual, since typically he is rambling and trying to be clever. I asked if he was still suffering from his recent injury....

A square has a side length of 5 units. Is it possible to cover this square with three squares each with a side length of 4 units?

a) Move three matches to make the largest possible number. b) Do so moving four matches.

Lucky numbers are 4 digits numbers that have the following property:they are equal to the sum of the fourth power of their digits. Therefore, they can be expressed as follow: 1000$a$+100$b$+10$c$+$d$ = $a^4$+$b^4$+$c^4$+$d^4$ What are all the lucky numbers? Please don’t use computers. (Hints:Use ...

100 people are sitting in a circle, where every person can see the 99 other people. All of them are wearing hats but they can only see the hats of other people, meaning they can't see their own hat. There are 99 white hats and 100 black hats. People start saying what they know about the color of ...