Sequence Puzzle
Find the next two terms in this sequence: 10, 11, 12, 13, 14, 15, 16, 17, 21, 23, 30, 33, ?, ?
Mate in 12
White to play and mate in 12. Sometimes thinking 12 moves ahead in chess is not as hard as it seems!
Slowing and Shrinking
Remove one letter from the word “SLOWING” to make another valid English word. Repeat this step until you are left with just one letter, ensuring every step results in an English word. What words did you make in the process?
Game the Coin Flip Game
A small company is losing money and the boss is looking for ways to cut costs. The boss is a foolish gambler, so he offers two employees the choice of either taking flat 10% pay cut, or playing the following…
Secret Translation
The CIA intercepted some messages from a criminal organization, some in English and some in an unknown foreign language or code. As a CIA analyst and translator, you have figured out the following sentences and their English translations, but you…
Unclear Perimeter
What is the perimeter of the outer rectangle? All angles shown are right angles.
Queen’s Mini Tour
Starting from this position, can the queen touch or pass through all nine highlighted squares in just four standard chess moves?
Bribing a Series of Guards
A criminal is planning an escape across a well-guarded bridge, which has a series of 9 guards, who each require a bribe of one coin in order to pass by them in either direction. The criminal can keep a stash…
Complete the Words
P _ _ _ N TD E _ _ _ STS T _ _ _C _ _ _ E R Which 3-letter word can be inserted into all four lines above to form complete words?
Take Back a Move Chess Puzzle
This creative Leonid Kubbel chess puzzle has white take back a move and then checkmate! White just made a move, but then realized there was a mate in 1 on the last move and missed it. What was white’s last…
Flipping Every N-th
There are 100 face-down cards. The first person that passes by flips over every card, the 2nd person that passes by flips over every 2nd card, and so forth – the n-th person that passes by flips over every n-th…
Street Number Puzzle
You were walking around on a major street with 5-digit street numbers (for example, 11213) and noticed one of the street numbers was special – any two consecutive digits formed a 2-digit perfect square (in the order the digits appeared…
Cryptic Pattern Puzzle
Replace the ?’s in each of these to complete the puzzle: Part 1 “Asia” is H“Cuffs” is S“Ender” is I“Redness” is F“Fuchsia” is ? Part 2 “Using” is E“Desist” is I“Visits” is E“Design” is ? Part 3 “Gross” is W…
Rigging a Vote
There are five candidates participating in an unusual election. There are four rounds of voting, and only two candidates participate in each round, with the winner moving on and the loser dropping out. This means first candidate 1 will run…
Island of Blue Eyes
There is an island known for its people with blue eyes, yet there is at least one green-eyed person on the island. No one knows the color of their own eyes, as there are no reflective surfaces on the island…
Five’s a Crowd
Try to place five points in (or on the perimeter of) an equilateral triangle with side length 10, as to maximize the distance between the points. What is the greatest possible distance between the two closest points?
Burning Ropes
You have two lengths of rope that take exactly 60 minutes to burn. The ropes burn unevenly so if you cut the rope in half, burning a half will not necessarily take 30 minutes. How do you precisely measure 45…
Boxes of Apples and Oranges
There are three identical boxes of apples and oranges, except one contains all apples, one contains all oranges, and one contains a mix. The boxes are labeled “apples”, “oranges”, and “apples and oranges” but all 3 boxes were labeled incorrectly!…