Linked Questions

3 votes
1 answer
3k views

Four coins on the corner of a rotating rectangular table [duplicate]

The game has two players (A) The leader (B) player (you) Four coins are placed on the corners of a rectangular rotating table. Some of the coins are facing head and some tail. Your goal is to arrange ...
sonus21's user avatar
  • 131
-1 votes
1 answer
724 views

open a box with 4 locks [duplicate]

You have 4 spacial locks with arrows on them, each facing up or down (you don't know the start order), on each corner of a box. You can only check if all of them are facing the same direction (all ...
king of puzzlers's user avatar
1 vote
0 answers
80 views

Attempt to turn all the switches on or off [duplicate]

Here is the puzzle for you. There are four boxes in front of you arranged in a circle. Inside each box is a switch that is on or off. You cannot see inside the boxes. Each turn you stick your hands ...
NielIGuess's user avatar
  • 1,074
43 votes
7 answers
4k views

The subtraction game

Alice and Bob play a game that starts by Bob picking a secret integer $N\ge100$. Then the game goes through several rounds. In every round, Alice picks an integer $x\ge3$. Every number can be picked ...
Gamow's user avatar
  • 45.9k
20 votes
4 answers
5k views

Four buttons on a table

I was asked lately (in an interview) to solve this puzzle, which is similar to the 4 cups on table puzzle. In a certain room there is a rotating round table, with 4 symmetrically located ...
Jay's user avatar
  • 335
14 votes
5 answers
2k views

Safecracking Puzzle

There is a combination safe with four switches on the front, each with three positions (low, medium, and high). If the switches are set into an opening combination, then when you try to open the safe, ...
Ajay's user avatar
  • 157
18 votes
4 answers
5k views

Four cups on a table

I didn't invent this myself, I heard it a long time ago and it stuck with me. Four glasses are placed on the corners of a square rotating table. Some of the glasses are facing upwards and some upside-...
Dsel's user avatar
  • 351
9 votes
3 answers
3k views

Sliding Bolt Puzzle - fastest solution (time-wise)

This is a follow-up question for the Sliding Bolt Puzzle. If you have not solved it yet, you might want to head there first, as the extended discussion of its solution in this question will contain ...
diabonas's user avatar
  • 998
13 votes
1 answer
482 views

Combination lock on a triangular rotating table

This puzzle is part of a serie. Inspiration: Sliding Bolt Puzzle Part 1: It's this one (-: Part 2: Combination lock on a pentagonal rotating table Puzzle You are trapped in a dark room. Just your ...
Vincent's user avatar
  • 518
6 votes
1 answer
411 views

Combination lock on a pentagonal rotating table

This puzzle is part of a serie. Inspiration: Sliding Bolt Puzzle Part 1: Combination lock on a triangular rotating table Puzzle After solving the 3 digits code in 27 tries (again, you just have the ...
Vincent's user avatar
  • 518