Start with a point on $(0,0)$. Every move, you must follow this rule: for a point $(m,n)$, if there are no points on $(m+1,n)$ or on $(m,n+1)$, then you can remove point $(m,n)$ and add points $(m+1,n)$ and $(m,n+1)$. For an integer $k ≥ 1$, the $k$th diagonal consists of all points $(m,n)$ with...

I recently found an extraordinary moremover online today. Have fun finding the solution! It’s White to move and mate in 19 moves! Bonus: Explain the title in relation to the solution! Jozef Lozek, Pat a Mat 27, December 1999

My first riddle. I hope you all enjoy! Aeneas was my forerunner, and I influenced Doom; Many a man have I condemned, I’m both elegant and crude; I delve through burning wickedness, to the dark and frozen liar; And I climb the mount of suffering, to reach Jehovah’s fire. Wh...

To commemorate the 77th Golden Globe awards, held today by the Hollywood Foreign Press Association, here is a little puzzle involving foreign actors. What do the following foreign actors have in common, and who is the missing actor at #2? Chris Hemsworth ? Ralph Fiennes Emma Thompson John Clee...

In this problem, you will be allowed to use some operations and additional digits from the basic approximation of $\pi=3.14$ having some penalties, as follows: Operations: Using basic operations and parenthesis ($ +, -, *, /, (),$) gives you 4 points per number Using additional operations with...

See if you can fill in all the blank letter tiles in this graph using the clues sets below. Each set of clues yields a name or word. The name or word is guaranteed to follow some connected path through the letter tiles. The arrows indicate the permissible directions that the path may trav...

TO, PD, FP, FCA, M, ? It is an acronym related to sports,games or something like that.

RF, 20, RN,19, ND, 16, PS, 14, ?, ? Look at the pattern, and find the next sequences.

Today I bring you another long and glorious selfmate that I have created. May you solve it with fun! It’s White to move and selfmate in 9 moves.

((9,10,12), (10,15,20), (24,50,?)) I am trying to find the answer but I can't find the Value.

A kid places three model cars on a long, straight track equally spaced apart. He sets each of them to a different speed (though he forgot the specific speeds). These cars are special, though: they have magnetic nubs on the end, so if a car catches up to another car ahead of it, they link up toget...

Can you guess the missing digits in the following multiplication? ??? x 3? = ???? Digits from 1 to 9 appear exactly once each. The goal is to solve it with as little calculation as possible.

This is my English adaptation of a popular riddle.

There are explorers that want to go as far in the desert as possible. One explorer can carry water for himself for 10 days. If they would all stick together, they would have enough water to go 5 days into the desert, then they would have to turn to have enough water to get back to the start. But ...