diff --git a/README.md b/README.md
index e924d0c..30a3972 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,41 @@
-# hello-world
+# effect-systems
+
+This repository contains collections of code snippets related to my
+[Effect Systems](https://jrpotter.github.io/posts/effect-systems/) blog post.
+The post is not yet publically available.
+
+> As I’ve begun exploring the world of so-called algebraic effect systems, I’ve
+become increasingly frustrated in the level of documentation around them.
+Learning to use them (and moreso, understanding how they work) requires diving
+into the internals, watching various videos, and hoping to grok why certain
+effects aren’t being interpreted they way you might have hoped. My goal in this
+post is to address this issue, at least to some degree, in a focused,
+pedagogical fashion. In particular, I’ll aim to build up an intution of the
+fused-effects, library, chosen because it seems to have the most active
+development, the smallest dependency footprint, and minimal type machinery.
+
+## Building
+
+This repository uses Nix for reproducible builds. First
+[install Nix](https://nixos.org/download.html) if you do not currently have it
+on your system. Afterward, enable [flakes](https://nixos.wiki/wiki/Flakes) by
+adding line
+
+```
+experimental-features = nix-command flakes
+```
+
+to `$HOME/.config/nix/nix.conf`. You may then use `nix build` and `nix develop`.
+To makes things easier, we recommend using [Home Manager](https://github.com/nix-community/home-manager)
+to install [direnv](https://github.com/direnv/direnv) and [nix-direnv](https://github.com/nix-community/nix-direnv).
+Once you run
+
+```bash
+$ direnv allow
+```
+
+from the root directory, `nix develop` will be automatically invoked each time
+a change is detected in `flake.nix` or you return to the directory.
 
 ## Formatting
 
diff --git a/app/Main.hs b/app/Main.hs
deleted file mode 100644
index 98f25e4..0000000
--- a/app/Main.hs
+++ /dev/null
@@ -1,4 +0,0 @@
-module Main where
-
-main :: IO ()
-main = putStrLn "Hello, World!"
diff --git a/cabal.project b/cabal.project
new file mode 100644
index 0000000..7e47e83
--- /dev/null
+++ b/cabal.project
@@ -0,0 +1,2 @@
+packages:
+  free-monads
diff --git a/hello-world.cabal b/free-monads/free-monads.cabal
similarity index 91%
rename from hello-world.cabal
rename to free-monads/free-monads.cabal
index 6018d8f..47848f9 100644
--- a/hello-world.cabal
+++ b/free-monads/free-monads.cabal
@@ -1,8 +1,8 @@
   cabal-version:      3.0
-  name:               hello-world
+  name:               free-monads
   version:            0.1.0.0
 
-  synopsis:           The Corner programming language.
+  synopsis:           Free monads implementation.
   -- A longer description of the package.
   -- description:
 
@@ -18,7 +18,7 @@
     CHANGELOG.md
     README.md
 
-common hello-world-common
+common free-monads-common
   default-language:   Haskell2010
   default-extensions: BangPatterns,
                       BinaryLiterals,
@@ -74,7 +74,6 @@ common hello-world-common
                       relude
   ghc-options:        -Wall
 
-executable hello-world
-  import:             hello-world-common
-  main-is:            Main.hs
-  hs-source-dirs:     app
+library
+  import:             free-monads-common
+  hs-source-dirs:     src