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Puzzlebomb – December 2016

Puzzlebomb LogoPuzzlebomb is a monthly puzzle compendium. Issue 60 of Puzzlebomb, for December 2016, can be found here:

Puzzlebomb – Issue 60 – December 2016 (printer-friendly version)

The solutions to Issue 59 will be posted around one month from now.

This will be the last regular monthly Puzzlebomb – in future, there will be occasional one-offs but regular editions are taking a break. If you have any ideas for puzzles, please send them in! Previous issues of Puzzlebomb, and their solutions, can be found at

The maths of the Grime Cube

Not content with already having five cubes named after him, internet maths phenomenon James Grime has now developed a new Rubik’s cube-style puzzle for internet maths joy merchants Maths Gear. I’ve been slightly involved in the development process, so I thought I’d share some of the interesting maths behind it.

Another name for a Rubik’s cube is ‘the Magic Cube’ – and Dr James Grime wondered if you could make a Magic Cube which incorporates its 2D friend, the Magic Square.

Paper about student use of a learning space in mathematics

Sheffield Hallam University Maths DepartmentOne of the nice things about working in mathematics at Sheffield Hallam University is the environment in which I work. The maths department is a big, open learning space for students surrounded by staff offices. It’s a busy place, full of activity and plenty of opportunities to interact with students and other staff.

This space was renovated for mathematics a little before I arrived. It was designed to enhance student engagement and to create this sense of community, to allow collaborative learning and encourage inter-year interactions.

Over the last year, we conducted a study of use of the space. This included observations of use of the space as well as questionnaires and interviews with students about their use of the space, including students who had studied in the department in the old and new locations.

The results have just been published as ‘The role of informal learning spaces in enhancing student engagement with mathematical sciences‘ by Jeff Waldock, Peter Rowlett, Claire Cornock, Mike Robinson & Hannah Bartholomew, which is online now and will appear in a future issue of International Journal of Mathematical Education in Science and Technology (doi:10.1080/0020739X.2016.1262470).

A more equitable statement of the jealous husbands puzzle

Every time I use the jealous husbands river crossing problem, I prefix it with a waffly apology about its formulation. You’ll see what I mean; here’s a standard statement of the puzzle:

Three married couples want to cross a river in a boat that is capable of holding only two people at a time, with the constraint that no woman can be in the presence of another man unless her (jealous) husband is also present. How should they cross the river with the least amount of rowing?

I’m planning to use this again next week. It’s a nice puzzle, good for exercises in problem-solving, particularly for Pólya’s “introduce suitable notation”. I wondered if there could be a better way to formulate the puzzle – one that isn’t so poorly stated in terms of gender equality and sexuality.