A puzzle by James Tanton:

King Tricho lives in a palace in which every room is a triangle:

Before retiring for the night he’d like to inspect it. Is there a path that will let him visit each room once and only once? He can start anywhere.

A puzzle by James Tanton:

King Tricho lives in a palace in which every room is a triangle:

Before retiring for the night he’d like to inspect it. Is there a path that will let him visit each room once and only once? He can start anywhere.

A pretty problem by August Vorrath. White to mate in two moves.

A wine merchant has three sons. When he dies, he leaves them seven barrels that are full of wine, seven that are half-full, and seven that are empty. His will requires that each son receive the same number of full, half-full, and empty barrels. Can this be done?

In his 1976 book *100 Numerical Games*, French puzzle maven Pierre Berloquin asks whether it’s possible to construct a magic square using the first nine prime numbers (here counting 1 as prime):

1 2 3 5 7 11 13 17 19

Is it?

By Hans Georg Matthäus. White to mate in two moves.

By François Paul Loquin. White to mate in two moves.

Here are five new lateral thinking puzzles to test your wits and stump your friends — play along with us as we try to untangle some perplexing situations using yes-or-no questions.

By Hermann Von Gottschall. White to mate in two moves.

ullage

n. the amount a container lacks of being full

Given a 5-gallon jug, a 3-gallon jug, and a limitless supply of water, how can you measure out exactly 4 gallons?

A classic puzzle from Jacques Ozanam’s *Recreations Mathematiques et Physiques*, 1723. Two slits (CD) and two holes (EF) are cut in a slip of paper, and a cherry stem is suspended as shown. The cherries are too large to fit through the holes. How can you free the stem and its cherries intact from the slip?