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Can you sort a stack of pancakes by size, from the smallest on the top to the largest on the bottom, using only a single plate and a spatula, flipping 2 or more pancakes at the top of the stack (possibly the entire stack) with each flip? How many flips does it take?

Join the ranks of the notables who've tackled this problem, including Bill Gates and David S. Cohen (a.k.a. David X. Cohen, writer & producer of The Simpsons and Futurama).

03/10/2017 - 18:55

Fold a long strip of paper in half several times. Can you see a pattern in the creases formed along the length of the paper? What sorts of route do we trace if we use the creases to direct our turns along a path?

02/28/2017 - 15:29

All the frogs want to trade places with the toads, and vice versa – but they have to follow some rules. If you can solve it in 1 dimension, try it in 2!

02/28/2017 - 16:33
03/25/2017 - 11:20

Is it possible to fold a strip of paper into a shape that can be “flexed”, revealing faces than weren't visible at the start?

02/28/2017 - 15:28

How does the circle leader keep spotting the lie?

02/26/2017 - 22:31

Imagine building a sponge by removing portions of a cube, then removing similar portions of the cubic pieces that remain, repeating this process n times. Can you build such a sponge out of smaller versions of the sponge, or other building blocks?

03/07/2017 - 08:02

In this classic puzzle (often used in job interviews), you are given 3 jars, the labels of none of which match their contents. How many samples must you draw from the jars, before you're able to correctly label them?

02/28/2017 - 15:53

Let your inner artist out, to paint a canvas using colored rectangles. But watch out: there are a few catches.

02/26/2017 - 16:08

In this game, checkers are removed from either end of a row of black and red checkers. But there's a catch: you can only remove palindromes (sequences that are the same, forward and backward).

02/28/2017 - 17:07