This puzzle is part 6 of the Double feature series (first part here). The series will continue in "Double feature: Weightier". Rules of Hitori1 Shade some cells in the grid. No number occurs in more than one unshaded cell on any row or column. Shaded cells cannot be adjace...

Just have this now what are all these acronyms refer to and what is the code ?

Can you help me figure out what word this riddle is about? "Not spun, or simply woven My skin as smooth as a mirror You stain my face, contort my body I can hold the greatest power And pass it with a glance Yet you are prone to cast me off Without a second thought Although sometimes when...

Can you paint every number from 1 to 8 with two colours, such that there are no distinct numbers $a, b, c$ of the same colour with $a+b=c$? For example, you cannot have 2, 3 and 5 of the same colour since $2+3=5$. Good luck!

Can you paint every number from 1 to 23 with three colours, such that there are no distinct numbers $𝑎,𝑏,𝑐$ of the same colour with $𝑎+𝑏=𝑐$? For example, you cannot have 2, 3 and 5 of the same colour since 2+3=5. You may need to use a computer to solve this. Here is a similar puzzle for nu...

There is a set of $10$ first natural numbers, $S = \{1,2,\cdots,10\}$. Alice picks a subset of it, say $A \subseteq S$. Bob picks a subset of it, say $B \subseteq A$. Charlie picks a subset of it, say $C \subseteq B$. Dave picks a subset of it, say $D \subseteq C$. Ho...

You have 5 numbers 1, 9, 3, 5, and 7 you need to arrange these number like Rules create 2 pairs from numbers above keep one of the number in the middle then apply this law 1st pair * last pair - middle number. after arranging and applying the above rules the result should be a num...

Which common thing do these words have uncommonly in common? mole kiss breath Note, that until you have not found the answer, it helps you find your way back to the real world.

If I wanted to describe it as a minimum problem, where I want to identify the minimum value of the constant for a certain matrix order, how should I do it?

Time to get back to Puzzling! Hangman game backward #12 - guess what the question was: fill in "a" - In some area it proves to be a big problem to kids / teens or even adults these day, which potentially does not exists thirty something years ago. fill in "e" - 2, 4 and 6 are the common numbe...

My brother showed me the following puzzle from some type of (IQ?) quiz game on his phone: 1 + 2 = 21 2 + 3 = 36 3 + 4 = 43 4 + 5 = ?? I am quite sure this was the original question asked. I pondered it for a while and had a few guesses, but none were accepted as "Correct." I als...

I've been discussing the logic puzzle where 100 logicians, all wearing blue hats, are trapped in a room and told: they can leave when a bell rings if they know they know they are wearing a blue hat, they are all perfect logicians and at least one of them is wearing a blue hat. The bell rings eve...

Here's another puzzle of this type. Perhaps my next one will be complex enough to require the full $72$ x $72$ size. Final answer: (5,2,5)