This is my first self-developed cryptographic puzzle. I hope it is neither too hard nor too easy for you to break, and that you enjoy it. Please do not only post the answer, but also your way towards it. You are Alan Turing 2.0 - a British intelligence officer trying to break newly created cod...

I stumbled upon a mathematical puzzle that goes like this: You have 2n coins that alternate between head and tail. For example, if n=3, then it looks like H T H T H T, where H = head and T = tail. To win the game, all coins must be either head or tail. The permitted move is alternating the face o...

A figure consists of 5 equal squares in form of a cross. Show how to divide it by two straight cut into 4 equal figures which will fit together to form a square. A mse told need to cut it from the vertices but how?

I spoke to Rock, Paper, and Scissors recently and asked them how they deal with their respective nemeses. Rock said: If I spend enough time around scissors, they’ll have a hard time moving eventually. Paper said: I never met a rock too hard for me to dig into and break through. Scissors ...

An entry in Fortnightly Topic Challenge #39: Deep Down in the Dungeon 1. The next room you enter is surprisingly well-lit and empty. There are two exits from it (need I say that the door through which you entered is an entrance and is not going to double as an exit?): a normal-sized locked doo...

Find the rule that is all correct on the left side, but not on the right side. If you don't know about bongard problems you can click here.

Note: Despite the fact that the clues appear to be cryptic ones they do not truly and completely follow the rules of cryptic clues. They do have some resemblance to them, though. A list of the clues (as they appear on the connect-wall): A cruel and oppresive ruler loses his ant and rules th...

An actor who danced to the time of my li', an ancient invention, a wizard with y, what most folk believe will come after you die. What am I? Arabian city with sky-scraping burj, marine trip for pleasure, vacation with splurge, with treasure or scavenger; ...

Let's say you have this base64 file. You can see there's a meme if you put it inside a decoder, but can you find anything else (a text file/image with text)? These are rules for a Hello World!-type challenge you can find and that's all you need to do. You don't even need to do the challenge to su...