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Recreational Maths Seminar – Picture-hanging puzzles

I hosted the first (proper) Aperiodical recreational maths seminar yesterday. We discussed the paper Picture-hanging puzzles, by Demaine et al. Click through to watch the YouTube recording of the session.

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I had a lot of fun, and it turned out I picked a particularly good paper to look at. I’m definitely going to try one of the more complicated puzzles this weekend at the big MathsJam.

I’m now going to waffle for a bit about the technicalities of the seminar, because I think a few people are interested and so I can gather my thoughts about it.

The format seemed to work OK. I started a Google+ hangout, invited everyone who had joined the event I set up on The Aperiodical Google+ account, and it all worked remarkably smoothly. I made sure everyone muted their microphones when not talking, to avoid distracting background noise, and encouraged people to use the text chat to ask questions or say when they’d like to speak.

I used the built-in Google+ screenshare feature to display the PDF of the paper, though I asked everyone to have their own copy visible so they could read ahead or linger on a section if they needed to. I think the image was fairly clear in the hangout, and it’s just about legible in the YouTube recording. I could’ve zoomed in another level or two to be sure it would look OK.

The attendees consisted of a couple of university lecturers, a couple of undergrads, and I think a couple of postgrads. I think everyone followed along fairly well, though we had to revise a few definitions from group theory. I think everyone joined in with a question or an explanation at least once, which was very encouraging. I was a bit worried at the start that everyone would sit in silence, waiting for me to tell them all about the paper.

There was a question at the end about how long it had taken me to read through the paper before the seminar. I deliberately didn’t read through it in advance. Either I would’ve got bored re-reading something I already understood, or I would’ve gone too quickly for everyone else to follow. Being unfamiliar with the paper meant there were several opportunities for other people to take over and explain bits, or answer questions asked by the others.

The whole thing took just over an hour. Unlike a physical seminar, people could join and leave without causing too much offence, so I was quite relaxed about not hurrying things along.

Thanks to everyone who took part. If you’re one of those people, I’d love it if you put a comment below with your thoughts on how it went, and any ideas you’ve got for how we could do things better next time.

I think fortnightly is a manageable period for the seminar, so there’ll probably be another one the weekend after next. Any suggestions for papers to discuss are welcome at

4 Responses to “Recreational Maths Seminar – Picture-hanging puzzles”

  1. Colin Beveridge Colin Beveridge

    One thing I might tweak to make it a little smoother next time is to have one person lead the discussion and another deal with admin stuff like making sure everyone’s added and keeping track of the text chat.

    I enjoyed myself immensely, despite it being completely not my field.

  2. Avatar Dana Ernst

    Cool! Thanks for doing this. I hope to be able to make one of these in the future. Hugh Denoncourt and I have been toying with the idea of doing something similar, but more specialized (e.g., combinatorics of Coxeter groups). We’ve experimented a little and there are a few features that I hope Google adds to Hangouts. For example, it would be great if you could display both the speaker and the document they are sharing. Also, some annotation tools (for PDFs in particular) would be nice, but this is easy to achieve with existing tools.


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