Exercise for the reader
More from Chalkdust

How to Expect the Unexpected
We review the fifth of this year's nominees for Book of the Year
Quarto in higher dimensions
Peter Rowlett is gonna need a bigger board
Covering infinity
Sophie Bleau uncovers the secrets behind covering maps
Can computers prove theorems?
And will we soon all be out of a job? Kevin Buzzard worries us all.
Two years of Chalkdust!
Here are some highlights of the first two years of Chalkdust!
Page 3 model: The Duckworth–Lewis method
Meet the Duckworth-Lewis method, 23, from Lancashire
