One of my students coded up some Toads and Frogs games last year and this semester wanted to improve the Elephants and Rhinos positions so they were all generated with mean value of zero.

The issue is that if you generate really random E&R boards, they are often either extremely unbalanced or there are very few moves available.

They got it working! Now you can play Elephants and Rhinos games where it's complicated to find and make the best moves. Try it out here:

https://kyleburke.info/DB/combGames/elephantsAndRhinos.html

(I don't want to say it's "hard" because you can still find them in polynomial time.)

#CombinatorialGames #UndergradResearch

Elephants and Rhinos

#Sprouts2026 was yesterday and it was great! Sprouts is our annual conference in abstract games (often #CombinatorialGames) where students present #UndergradResearch for the contributed talks.

Here are my summaries of the talks: https://combinatorialgametheory.blogspot.com/2026/04/sprouts-2026-summaries.html

Here are a bunch of my after-the-fact thoughts: https://combinatorialgametheory.blogspot.com/2026/04/sprouts-2026-afterthoughts.html

I need to make sure I figure a bunch of those things out in time for next year!

Thank you to everyone who attended and especially to all of our great speakers. Craig and I agreed that we're very lucky to get such amazing talks!

Sprouts 2026 Summaries

Combinatorial Game Theory blog. Algorithmic, computational complexity, CGT, abstract games, Nim, Col, Snort, Kayles.

The #Sprouts2026 program is coming along! We have nine contributed talks all lined up (from undergrads) and our keynote info should be going up later this week. https://kyleburke.info/sprouts/sprouts2026/

#CombinatorialGames #UndergradResearch

Sprouts 2026

A while ago, I wrote about Welter's game: a simple combinatorial game where two players take turns moving coins down a line until no moves are possible. It has some curious connections to coding theory, but for our purposes, it's just a little game to play over the holiday.

However, the game setup implicitly discriminates against people who don't have any coins, and we can't have that, so here's a web version: https://welter.fuglede.dk/

#maths #combinatorics #games #combinatorialgames

Welter's Game

A combinatorial strategy game: move coins along a number line and force your opponent into a losing position.

#ICCGTJ is already over! The last day of talks great! Here are my summaries: https://combinatorialgametheory.blogspot.com/2026/03/international-cgt-in-japan-day-four.html

Thanks to all the organizers and to everyone spreading #CombinatorialGames in Japan!

International CGT in Japan, Day Four

Combinatorial Game Theory blog. Algorithmic, computational complexity, CGT, abstract games, Nim, Col, Snort, Kayles.

International CGT in Japan, Day Three

Combinatorial Game Theory blog. Algorithmic, computational complexity, CGT, abstract games, Nim, Col, Snort, Kayles.

Day two of #ICCGTJ was excellent! We had multiple talks by teams of high schoolers, which is absolutely amazing. Here are my quick summaries: combinatorialgametheory.blogspot.com/2026/03/international-cgt-in-japan-day-two.html

#CombinatorialGames

Here are my summaries of the first day of talks at the International Conference on CGT in Japan (#ICCGTJ): https://combinatorialgametheory.blogspot.com/2026/03/international-cgt-in-japan-day-one-talks.html

Conference site: https://deguchikikaku.sakura.ne.jp/

#CombinatorialGames

International CGT in Japan, Day One Talks

Combinatorial Game Theory blog. Algorithmic, computational complexity, CGT, abstract games, Nim, Col, Snort, Kayles.

Added another game to my playable list of games. (I implemented this year ago, then somehow lost it.) You can now play #Slimetrail: https://kyleburke.info/DB/combGames/slimetrail.html

#CombinatorialGames

Slimetrail

Hi folks -- I am pleased to announce the public release of Tetro Domain, a small #pico8 strategy game playable on desktop web and mobile: https://puleo.itch.io/tetrodomain

As I mentioned in a previous post, this game is built around the concept of the strategy-stealing argument: its rules have been designed so that there is a nonconstructive proof that the first player always has a winning strategy on any board the game can generate. As the proof is nonconstructive, it does not actually provide any indication of what the winning strategy *is* -- but I believe it ends up being an interesting little strategic challenge to work out the winning strategy that is guaranteed to exist.

The computer opponent you play against is not *especially* strong, but I've found it to be strong enough to sneak out the occasional win against me if I let my guard down. I'm biased, of course, but I've found playing it on mobile especially to be an entertaining way to get a quick strategy fix within a couple of minutes.

I think that *probably* the strategy-stealing argument could be pushed much further to a game with more complexity than this game has -- this design is fairly simple but I'm quite pleased with how it came together.

#gamedev #indiedev #combinatorialGames

Tetro Domain by puleo

itch.io