Latest Issue

Enigmas and puzzles

By Ian Stewart   August 2007

In the tiny market square just off the Street of the Coppersmiths in Renaissance Pisa, you could find everything from Arabian spices to local cabbages. Maria was looking for wildfowl. She carried a pouch containing 30 identical silver coins, with instructions from the Contessa to spend them all, and to come back with exactly 30 birds. “And I need at least one duck,” the Contessa had added.

Maria expected her task to be easy. But when she reached the fowl merchant’s stall, she got a shock. “Two coins for a duck?” she cried in horror. “They were half that price…

Register today to continue reading

You’ve hit your limit of three articles in the last 30 days. To get seven more, simply enter your email address below.

You’ll also receive our free e-book Prospect’s Top Thinkers 2020 and our newsletter with the best new writing on politics, economics, literature and the arts.

Prospect may process your personal information for our legitimate business purposes, to provide you with newsletters, subscription offers and other relevant information.

Click here to learn more about these purposes and how we use your data. You will be able to opt-out of further contact on the next page and in all our communications.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

We want to hear what you think about this article. Submit a letter to

More From Prospect