Eric Severson

Math teacher at Proof School.
Place for my nerdy interests: some combination of cool math stuff and card games.

[Eric Severson @EricESeverson]

@bsweitz123 Aww man i want to try playing these, lmk if you’re heading back to the bay any time soon and bring them.

I finally made my first cube this past year originally to share with my students. The design process is so fun

[Eric Severson @EricESeverson]

Add polar and rectangular grids like my old tool, but now also draw text and pictures just for fun. And the GeoGebra tool I built last year didn't have phase portraits, so we spend a bunch of time manually pasting phase portrait pictures in from another tool

[Eric Severson @EricESeverson]

https://t.co/VAzZFCvJ9Y

Emboldened by the fun 3d phase plane warping widget I made a few hours ago, I set Fable on a goal to recreate my master plotter from last year, but in an all-in-one-widget. It's already got way way more features that I could have even dreamed of last year

[Eric Severson @EricESeverson]

I've also got a pipeline going where it reads through all the slides I leave of my boardwork (along with all the project context it's building, timestamps of when things got written on my smartboard) and then writes me up these notes of what happened that day in class

[Eric Severson @EricESeverson]

https://t.co/HtwYNCdAG9

Running my first Claude-ified math class, doing complex analysis again, building off a super visual class I developed for high schools last year.

Had a nice idea after class for an animated version of a textbook figure I had showed

[Eric Severson @EricESeverson]

@AnalysisFact A nice smoothed equilateral triangle comes from the intersection of these two curves, which as I mentioned in the comment comes up in a nice way as the solution to the 3 dimensional ODEs of Rock-Paper-Scissors dynamics
https://t.co/0htbddjqHH

[Eric Severson @EricESeverson]

I made a cube!
As a summer project I put *way* too much time getting ready this school year's iteration of Magic club
Designed to be straightforward to draft for new players, heavy on signpost gold cards for some tried-and-true themes for each 2-color pair
https://t.co/wOpIN8BLj4

[Eric Severson @EricESeverson]

I always get so hooked on the Omniscience drafts on MTG arena. This is probably the best deck I've had yet, 5-0 with multiple turn 1 kills so far.

[Eric Severson @EricESeverson]

@bsweitz123 I hadn’t cashed in a very long time. Maybe core set had easier competition.
Was fun to be back, will try to make more of the opens going forward. It’s nice how often yall are doing limited ones.
Idk if/when the next will be, but would be cool to have one for pioneer masters

[Eric Severson @EricESeverson]

4-0 my second draft for $2k in the arena open. Even got to go to dance this morning between the 2 drafts

[Eric Severson @EricESeverson]

3-1 in my first Foundations draft, off to the final draft of the Arena open

[Eric Severson @EricESeverson]

Tried one run of the Arena open at the last minute. First games I'd played of the format, and first time trying B03. Didn't think my deck was very good, but got lucky in some close games

[Eric Severson @EricESeverson]

This class has been another good excuse to keep leveling up my geogebra skills. You can click through all the steps of the argument and move the points around at: https://t.co/kb8oN8ZR4b

[Eric Severson @EricESeverson]

Teaching Euclidean Geometry right now, and today went through my favorite proof of the class so far: the side-splitter theorem (https://t.co/pXdxSCoPr4), a key lemma in proving triangle similarity rules:
BD/AD = CE/AE in the figure below

[Eric Severson @EricESeverson]

Taking the ratio of green area to blue area, the common purple height cancels out and we recover the key ratio.
A symmetric argument works on the right side for the ratio of green to red areas. Finally, because blue and red triangle areas match, we recover the identity.

[Eric Severson @EricESeverson]

@Trumpetman__ Playing mostly B01 over here, and smaller sample size, but similarly had a lot of success.

It might also be the volume of less experienced players coming out to play the Lord of the Rings set on Arena.

[Eric Severson @EricESeverson]

@argzax Resized the colored edges so it's easier to see the triangle and the corresponding chord segment.

The (n choose 3) identity as the sum of products is one of my favorite, nice to see its proof contained within this visual argument.

[Eric Severson @EricESeverson]

Was just remarking how the teaser to the video does a really effective job getting the viewer to engage with the problem, more so than just having us pause in the midst of a big video explanation. And as an example, I got derailed for an hour thinking more about the problem...

[Grant Sanderson @3blue1brown]

The puzzle below is a famous cautionary tale in math. But there's more to it than just coincidence, and on the YouTube version, we dig into what's really going on.

Full explanation: https://t.co/KExRH7X4yK

[Eric Severson @EricESeverson]

@argzax Ahh perfect now I see the bijection! The chord segment goes to the middle vertex in the triangle (green), and is just below the edge (green) between the other two (blue) vertices.