@mbonsma@mastodon.social

Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · May 25, 2026

Replying to @haraldkliems@fosstodon.org

@haraldkliems@fosstodon.org This paper does include that actually!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

Replying to @Andres4NY@social.ridetrans.it

@Andres4NY@social.ridetrans.it yes, definitely. Other research (with different methods) has found the opposite, and I don't feel like there's a good explanation for why it should be lower for e-bikes.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

Replying to @ansible42@social.ridetrans.it

@ansible42@social.ridetrans.it the motor stops boosting at 25, yes. I've definitely gone faster than the limit on my e-bikes if going downhill, for instance.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

Replying to @mbonsma@mastodon.social

These rates are an order of magnitude higher than injury rates for driving in Canada, by comparison (0.3 injuries or fatalities per million km in 2023). But I would argue that per distance is not the right comparison for cars vs. bikes, and something more like rate per trip would be better. Canadians drive something like 15,000 km per year on average. Bike commuters' average trip is 20 minutes, so even if you biked to work every weekday, you would still be under 4000 km biked for the year.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

Replying to @liilliil@mastodon.online

@liilliil@mastodon.online this one is an Urban Arrow, a brand from the Netherlands but sold in bike shops elsewhere!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

A finding that e-bike injury risk in Oslo, Norway is *lower* than conventional bike risk after adjusting for distance traveled.

Caveat for North American readers: e-bikes in the EU are speed-limited to 25 km/h.

https://findingspress.org/article/157852-relative-injury-risk-of-e-bikes-and-conventional-bicycles

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

Replying to @liilliil@mastodon.online

@liilliil@mastodon.online the bike or the bagels? 😅

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

Replying to @ryanprior@mastodon.social

@ryanprior@mastodon.social @rasterweb@mastodon.social This is actually in Toronto (I think in Montreal they don't have to specify that the bagels are Montreal-style?) Yes - they're more dense and a bit sweet. Once you get hooked, you can't stop!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 29, 2026

Replying to @michaelgemar@cosocial.ca

@michaelgemar@cosocial.ca our convenient Kettlemans location closed and this is a location we can get to semi-regularly. They're just as good IMO! I also go to Bagels on Fire on Queen or Bagel Time, both good.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 25, 2026

Cruising around in my SUV (Snack Utility Vehicle)

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 24, 2026

Replying to @hanscees@ieji.de

@hanscees@ieji.de pretty accurate!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 24, 2026

Replying to @raynerlucas@mastodon.social

@raynerlucas@mastodon.social love it

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 24, 2026

Tried to sign off with "best" and wrote "beset" instead, which seems appropriate

Beset,
Madeleine

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 07, 2026

Replying to @ellie@ellieayla.net

@ellie@ellieayla.net heck yes!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Apr 06, 2026

Curious about cargo bikes or biking with kids? Seasoned pro interested in meeting bike friends? Come to our cargo bike meetup on April 18 @ Withrow Park!
#BikeTO #CarryShitOlympics

https://www.eventbrite.com/e/cargo-bike-meet-up-test-ride-tickets-1986679250117?utm-campaign=social&utm-content=attendeeshare&utm-medium=discovery&utm-term=listing&utm-source=wsa&aff=ebdsshwebmobile

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 19, 2023

Replying to @kbob@chaos.social

@kbob@chaos.social very cool, thanks for the contrasting data point!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 15, 2023

Replying to @platkus@mastodon.social

@platkus@mastodon.social my dude, laying out all the pieces flat is ALSO in the very first post in this thread! You're replying to the third post! https://mastodon.social/@mbonsma/111564828670828672

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 14, 2023

Replying to @platkus@mastodon.social

@platkus@mastodon.social this is a weird hill to die on, the parameters are very clear both in the paper and later in this thread https://mastodon.social/@mbonsma/111564845145935604

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 14, 2023

Replying to @Kencf618033@social.linux.pizza

@Kencf618033@social.linux.pizza we are working on the 3D version now! The big question is what physical analogy to use. I think popped corn is a great example - they're not exactly spheres, but assuming spherical packing would probably give you a very good estimate of the volume. But what would "assembled" popcorn be? 🤔

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 14, 2023

Replying to @TomSwirly@toot.community

@TomSwirly@toot.community @stillmoms@mastodon.social you are very welcome to develop a more comprehensive theory of puzzle packing area!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 14, 2023

Replying to @platkus@mastodon.social

@platkus@mastodon.social we and you are making different assumptions about what constitutes the area of a puzzle. Our question was "how much area does it take to lay out all the pieces in a single layer", while of course in the box they don't need to be in a single layer. In the extreme case, you could stack every piece on top of the others and say the area of an unassembled puzzle is 1 piece. That's fine! Just not what we were trying to figure out.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @Chancerubbage@mastodon.social

@Chancerubbage@mastodon.social @gruber@mastodon.social I would argue that you don't need an extra full puzzle area for assembly - at least in my experience, some pieces hang out inside the partially assembled puzzle during the process. You definitely need *some* area to work, but as soon as you start assembling, the total area starts to go down.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @claralistensprechen3rd@friendica.myportal.social

@claralistensprechen3rd it is, that's exactly the point! But the *unassembled* puzzle takes up more space, and we wanted to know how much more!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @TomSwirly@toot.community

@TomSwirly@toot.community two things: first, we did not specifically select for "normal" puzzles and the theory still works, aka most puzzles have pieces that are kind of vaguely square even with nubs and holes. One of the puzzles was a very large linear children's floor puzzle. Second, I'm not convinced it *would* break down even if the pieces had a wider distribution of shapes, because they might still pack according to circles with the average area, on average. More data needed!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @BerndGoldschmidt@mastodon.social

@BerndGoldschmidt@mastodon.social it might break down for some very irregular piece shapes, but it seems like not really! That's the beauty of the simplification, anything "not square" about the pieces is a small variation that seems to not matter.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @mbonsma@mastodon.social

So there you have it: you'll need a puzzle table just under twice as big as your assembled puzzle in order to not resort to the box lid or that random side table. Grab a puzzle and impress your relatives this holiday season with your predictive powers!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @mbonsma@mastodon.social

We were surprised that the unassembled area didn't depend on the number of puzzle pieces. The intuition is this: if you have a small number of large pieces, the gaps between pieces are big, but this is multiplied by a small total number of pieces, and vice versa for small pieces.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @mbonsma@mastodon.social

The results were the most incredible agreement between theory and data I've ever seen in over a decade of being a physicist. I think I gasped when I saw this plot. Without any fitting, our simple theory *very accurately* predicted the unassembled area of all these puzzles.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @mbonsma@mastodon.social

We built 9 puzzles across a variety of total sizes and with piece numbers ranging from 9 to 2000. We laid out all the pieces flat, trying to be realistic by not paying much attention to how they were arranged and not spending time trying to get them closer together.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @mbonsma@mastodon.social

We derived a theory with a "spherical cow in a vacuum" approach: we approximated each puzzle piece area as a circle, then calculated the area of the circles packed together. Our prediction: the unassembled area is sqrt(3) times the assembled area. Then we took data.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @mbonsma@mastodon.social

TL;DR: an unassembled jigsaw puzzle takes up an area that is the square root of 3 times the area of the assembled puzzle, or about 1.7 times the assembled area. This is *independent of the number of pieces*.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

Replying to @mbonsma@mastodon.social

This work was a pandemic collaboration between me and the brilliant Kent Bonsma-Fisher, with assistance from our toddler and cat. The result, in his words, was "the cleanest dataset I have ever collected." Today our results are public on #arXiv!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Dec 12, 2023

We've all been there: it's puzzle time, but once you dump out the pieces and start laying them flat, you realize you don't have enough space on your table. Join me as we use physics to find out ✨HOW BIG A TABLE YOU NEED FOR YOUR JIGSAW PUZZLE ✨

https://doi.org/10.48550/arXiv.2312.04588
#SciComm

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Feb 16, 2023

Replying to @snoda@mstdn.ca

@snoda@mstdn.ca I used 15 and over because I was trying to estimate the fraction of people who could get a license who don't have one. I agree, younger kids also need independence and car dependency hurts them too.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Feb 16, 2023

Replying to @DrivingUsMad@urbanists.social

@DrivingUsMad@urbanists.social wow, that's really high!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Feb 15, 2023

Replying to @tobypinder@mastodon.social

@tobypinder@mastodon.social such a good point - we view license suspension as a cruel punishment only because the other options are terrible, and it means people are allowed to drive who really really shouldn't.

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Feb 15, 2023

Replying to @RoyBrander@urbanists.social

@RoyBrander@urbanists.social good catch!

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Madeleine Bonsma-Fisher, PhD @mbonsma@mastodon.social · Feb 14, 2023

Your periodic reminder that MANY people can't drive, including all children.

Even among the license-eligible age group, many people don't drive. In Canada there were about 26.5 million licensed drivers in 2018, or about 85% of the population over 15. That leaves almost 1 in 7 teens and adults without driving as an option to get around.

This is your periodic reminder that car dependency is ableist and exclusive.

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