“A Reuleaux triangle is the simplest and best known Reuleaux polygon. It is a curve of constant width, meaning that the separation of two parallel lines tangent to the curve is independent of their orientation.” – Wikipedia.

I’ve noticed the Reuleaux triangle, a lovely and rounded three-pointed shape all over Amsterdam. Two examples ranging from the relatively substantial to the most mundane are the shapes of windows in the Plan-Zuid, Berlage designed homes in the city’s south, and the shapes of common beer coasters in bars all over the city.

I like this shape. Its roundedness makes it playful and approachable. I didn’t know there were shapes out there I had never encountered before. It’s new to me. It feels distinct to this region of the world, and specifically, this city.


Enjoy these GIFs of the reuleaux triangle – I made them using the deep reds and purply blacks that characterize Amsterdam — this undulating and cozy city.


Update: Wild news, readers! It turns out there was a significant Reuleux Triangle in Amsterdam I failed to mention before, one so big that it’s amazing I didn’t see it until now. It turns out that the entire city is a reuleux triangle!

That’s right – on many scales from the canal belt to the ring road that surrounds the city, Amsterdam is shaped like a large, rounded triangle.

amsterdam triangle