Puzzle Library
Browse our hand-curated puzzles
All Puzzles
77 puzzlesBrowse every puzzle in the library
Starter Puzzles
13 puzzlesPuzzles for new hikers starting out!
Puzzles By Difficulty
Easy
41 puzzlesSingle-insight puzzles accessible with everyday reasoning. One "aha!" moment required.
Medium
26 puzzlesMulti-step puzzles requiring persistence and systematic thinking. High school mathematics sufficient.
Hard
7 puzzlesRequires specific techniques like induction, graph theory, or advanced proofs. Multiple interconnected insights needed.
Expert
2 puzzlesDeep mathematical reasoning or research-level thinking. Advanced proof techniques and mathematical background required.
Open
1 puzzleCurrently unsolved problems with no known solution. Active areas of mathematical research.
Recommended Puzzles
Hummingbird
A train leaves Oakridge at 20 km/h, headed for Fairhaven. At the same time, another train leaves Fairhaven at 30 km/h, headed for Oakridge on the same track....
Randomised Ice Cream
For Employee Day, your company is offering everyone free ice cream, and you somehow find yourself at the front of the queue. The vendor manning the ice cream...
Average Salaries 2
Back in [[puzzle ]], 12 employees came up with a method to find out their average salary without revealing their individual salaries to anyone. Here’s the...
The Keyboard Prank
Anne comes into the office to find that her co-workers had played a prank on her. The keycaps on her keyboard had been shuffled such that if she types out a...
100, 10, 1
Your friend, Cole, shows you his first attempt at programming: a calculator that takes in a binary sequence and does an arbitrary computation on it: If the...