What's up in

The solution to this month’s puzzle gets to the bottom of the famously ambiguous Sleeping Beauty probability problem.

Like a visually ambiguous Necker cube, the famous Sleeping Beauty problem can be perceived in two seemingly valid ways.

The solution to this month’s puzzle explains how to design a Sudoku square to figure out the likes and dislikes of four or eight finicky friends.

For this month’s puzzle, design a Sudoku square to figure out the likes and dislikes of four finicky friends.

The solution to this month’s puzzle explains how to find a rule behind a given sequence of numbers and challenges readers to take on a ‘lovely’ unsolved problem.

Can you infer the simple rule behind a number sequence that spikes up and down like the beating of a heart?

The solution to this month’s puzzle explains the artful mathematics behind symmetrical patterns.

Can you generate aesthetically pleasing, symmetrical curves with two numbers and a simple mathematical function?

The solution to this month’s puzzle uses both mathematics and psychology to explain trouble with choosing the fastest route.