Hello I will send you messages from time to time, they will get trickier and more difficult. I can't tell you my name. You will have to do the cipher. This one is quit easy and won't be that challenging. But when you answer the question I have given you please be honest. Thank you. - Unknown. 01...

Really wanted to share this, I hope this is the right section/website to do so. I've written a cipher for my level 3 Java class in university. We had free reign on the assignment we wanted to do so I made a somewhat secure messaging app. Let's put you in the scene. You're working a long boring jo...

Take a square grid of size $a\times b$, with all squares being off. You can tap a square, to reverse the state of that square and all squares located in the same column and row as the tapped square. Your goal is to turn on all the squares. What's the minimal amount of moves required to solve ...

What is the hardest slitherlink board you have seen/solved/tried to solve? I've tried googling for some hard ones but came up with simple ones or sites describing what slitherlink even is... So in other words - please provide examples of some hard/hardest boards you know (standard slitherlink rul...

I can not figure out this to safe my life & neither can my husband & he is a math whiz too. But here's the riddle, 8898=7,4566=2,1203=1,4566=2,5464=1,7774=09856=4,8764=3,4500=? Thank you for your help.