Mystery Hunt 2023

This is a retro-post for the Mystery Hunt 2023, for which I played a somewhat minor role on the organizing team (teammate). You can play at There is an ongoing list of write-ups about the hunt being kept at, and you may also be interested in the reddit AMA from teammate. Puzzle shoutout… Continue reading Mystery Hunt 2023

A common type-error on the OTIS application

There's a common error I keep seeing on OTIS applications, so I'm going to document the error here in the hopes that I can pre-emptively dispel it. To illustrate it more clearly, here is a problem I made up for which the bogus solution also gets the wrong numerical answer: Problem: Suppose $latex {a^2+b^2+c^2=1}&fg=000000$ for… Continue reading A common type-error on the OTIS application

Two updates on the EGMO textbook

Couple Thanksgiving presents for y'all: Errata List now on GitHub The list of errata is now version controlled on GitHub: now you can actually see a changelog of the ocean of typos as they come in.Shout-out to the crew working on the Japanese translation of the book for finding way more errors than I… Continue reading Two updates on the EGMO textbook

Why Evan does not like JavaScript as a first language

Some people have asked me why I anti-recommend JavaScript for beginners on my website FAQ. This post will try to give a few reasons why. Some notes: I’m referring to base JS. I like TypeScript a lot for example (it’s high on my tier list of programming languages for beginners). And I know about eslint,… Continue reading Why Evan does not like JavaScript as a first language

Sometimes the best advice is no advice

信言不美,美言不信。 I get a lot of questions that are so general that there is no useful answer I can give, e.g., "how do I get better at geometry?". What do you want from me? Go do more problems, sheesh. These days, in my instructions for contacting me, I tell people to be as specific as… Continue reading Sometimes the best advice is no advice