Web-based implementation of Isopath, a zero-sum boardgame invented by pocket83
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This is a web-based implementation of Isopath, a zero-sum boardgame invented by pocket83.

If you don't know the game, you can learn more in his original video (rules start at 15:45).

Playing the game

You can play it right now at https://isopath.jes.xxx/

You'll need to know the rules, the graphics are bad, and some of the UX is a bit clunky.

Important non-technical future work would include creating reading materials that introduce beginners to the game.

Writing an AI


See public/js/ai/random-moves.js for a basic example. You need to:

  • create a new class implementing move() that returns the move you want to play whenever it gets called
  • call IsopathAI.register_ai(), passing it a short name for your AI, a long name, and a generator function that creates an instance of your class

You do have direct access to the Isopath object (it's passed as the only argument to your constructor), but you should avoid manipulating it at all. Treat it as read-only. This is not considered a bug as your code has complete access to everything in the window anyway.


Another option is to read the API file and speak websockets (with the help of stdio-websocket if you prefer). This has the advantage that you can write it in whatever langauge you like, and run it remotely, but the disadvantage that you need to implement the game rules yourself. I intend to implement an example to show how to do this.


If you only want to play locally, you should be able to load public/index.html in your favourite web browser.

If you want websocket support, you'll need to get some Perl on. The easiest way to do this on Ubuntu is:

$ sudo apt install cpanminus build-essential
$ sudo cpanm Mojolicious
$ morbo isopath

And then you can visit http://localhost:3000/ and play it. Mojolicious is an excellent web framework for Perl (used here for its websocket support). morbo is a program that runs a Mojolicious application single-threaded and restarts it whenever the code changes.

If you want to run it in a "production" environment, you'll want to use hypnotoad instead of morbo, and you'll probably want a config file. Create a file called isopath.conf in the root directory of the repo, with contents like:

{hypnotoad => {listen => ['http://*:9008'], workers => 1}}

That will instruct hypnotoad to listen on port 9008 and run 1 thread. Don't start more than 1 thread else the websockets for the two players of a game will sometimes be in different threads and therefore unable to communicate with one another. Running in hypnotoad also causes Mojolicious to run in "production" mode instead of "development" mode which (among other things) prevents it from leaking so much internal state in error pages.

Start it (and restart it, whenever you want) with:

$ hypnotoad isopath

Contact me

Please email james@incoherency.co.uk to discuss anything remotely Isopath-related!