Welcome to MindCipher, a social repository of the world's greatest brain teasers, logic puzzles and mental challenges.
8 1 Three Idols
Here's a classic: Three gods A, B, and C are called, in some order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a comp ...
Hard
10.0
5 7 Psycho Killer
While at the funeral of her mother, she met a man whom she did not know. She thought he was amazing, her dream guy, and she fell in love with him but never asked for his number and could not find him ...
Submitted by Valentin
Doable
3.3
6 2 Grey Squares Illusion
Square A is the exact same shade of gray as square B. It's true, check out the reconstruction.
Doable
6.0
3 2 Time To Fuse
You have a string-like fuse that burns in exactly one minute. The fuse is inhomogeneous, and it may burn slowly at first, then quickly, then slowly, and so on. You have a match, and no watch. How do ...
physics logic rates Submitted by Valentin
Doable
4.7
3 2 Up and Down
Explain the following scenario: A man lives on the twelfth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets int ...
Submitted by Valentin
Hard
7.3
4 3 The Female Star
My first two letters are a man. The first three a woman. The first four are a brave man. And in whole I am a brave woman.
riddle word puzzle Submitted by Valentin
Doable
3.3
2 5 The Cabin
There is a man lying face-down, dead, in the middle of a cabin. The cabin is in the middle of the woods. There are windows, but they do not open. What is going on?
Doable
5.3
4 2 Boys and Girls
To help solve an acute national over-population problem, a government issues a radical decree that families must stop having children as soon as they have had one son. After a while, there are some ...
Doable
5.4
3 3 Guilty Innocence
I am a drug dealer. I have been questioned by the police with all of my drugs surrounding me, but I was not arrested. Why?
Easy
2.6
2 4 Cooking Time
A cook must put a souffle exactly 9 minutes at the oven, but he only have a 7 minutes hourglass and a 4 minutes hourglass. How can he measure 9 minutes with those clocks?
logic Submitted by Ravi
Doable
6.6
3 3 Products Algorithm
Given an array A[1...N] of integers, create an array O[1...N] where O[i] = the product of all elements in A except for the ith element. For example, if N = 3, and A = {6, 4, 2}, O = {8, 12, 24} The t ...
Doable
4.0
3 Gone Camping
Camp Crona’s cook, Allison, was just about to begin preparing the picnic lunch for all the campers. She already knew she needed to fill 55 bowls of the same size and capacity with the same amount of fo ...
mathematics Submitted by Aakash
Easy
2.9
3 5 Don't Mate in One
This problem was first publicized by Karl Fabel, a German chess problemist. Find a move for white that will not result in an immediate checkmate of the black king.
logic chess Submitted by Aakash
Hard
7.0
4 2 Don't Eat Me!
Would you rather a crocodile attack you or an alligator?
Submitted by Aakash
Doable
4.7
2 2 Cut the pizza into 11 equal slices with a wrist watch
Tools: (1) A wrist watch and (2) a normal knife Goal: Slice a pizza into 11 equal pieces
Hard
7.3