diff --git a/._config.yml.~undo-tree~ b/._config.yml.~undo-tree~
new file mode 100644
index 0000000..9858df6
--- /dev/null
+++ b/._config.yml.~undo-tree~
@@ -0,0 +1,13 @@
+(undo-tree-save-format-version . 1)
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+nil
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diff --git a/.shell.nix.~undo-tree~ b/.shell.nix.~undo-tree~
new file mode 100644
index 0000000..5e81f1a
--- /dev/null
+++ b/.shell.nix.~undo-tree~
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+(undo-tree-save-format-version . 1)
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+nil
diff --git a/_config.yml b/_config.yml
index c5b94c0..6712969 100644
--- a/_config.yml
+++ b/_config.yml
@@ -5,13 +5,14 @@ title: "rachel.cafe" # the name of your site, e.g. ACME Corp.
 plugins:
   - jekyll-feed
   - jekyll-katex
-  - jekyll/agda
   - jekyll-minifier
+  - jekyll/agda
 
 exclude:
   - "*.agdai"
   - "readme.md"
   - "LICENSE"
+  - "shell.nix"
 
 katex:
   rendering_options:
diff --git a/_drafts/.the-algebra-in-algebraic-datatypes.md.~undo-tree~ b/_drafts/.the-algebra-in-algebraic-datatypes.md.~undo-tree~
new file mode 100644
index 0000000..ef0599d
--- /dev/null
+++ b/_drafts/.the-algebra-in-algebraic-datatypes.md.~undo-tree~
@@ -0,0 +1,4 @@
+(undo-tree-save-format-version . 1)
+"14b4fac3fb89459c858bfc19e2649db580c097ce"
+[nil current nil nil (25784 9131 42808 229000) 0 nil]
+nil
diff --git a/_drafts/haskell-in-a-category.md b/_drafts/haskell-in-a-category.md
deleted file mode 100644
index 3d66a67..0000000
--- a/_drafts/haskell-in-a-category.md
+++ /dev/null
@@ -1,10 +0,0 @@
----
-layout: post
-title: "Haskell, Categories and Algebra"
----
-
-some general stuff about haskell and categories as well as algebraic datatypes, F-algebras and some concrete examples of fixpoint constructions and catamorphisms
-
-<!--more-->
-
-
diff --git a/_drafts/the-algebra-in-algebraic-datatypes.md b/_drafts/the-algebra-in-algebraic-datatypes.md
new file mode 100644
index 0000000..0c0d67a
--- /dev/null
+++ b/_drafts/the-algebra-in-algebraic-datatypes.md
@@ -0,0 +1,62 @@
+---
+layout: post
+title: "The algebra in algebraic datatypes"
+---
+
+In this post I will explore the algebraic properties of Haskell's types, give an informal description of category theory, F-algebras, homomorphisms, catamorphisms and a roundabout way to write a `foldr` that recurses backwards.
+
+<!--more-->
+
+# Algebra on types in Haskell
+* Basic algebraic properties
+  * Products, Either, Functions
+  * Non-recursive datatypes
+  * Algebraic equivalences over types
+	
+# Thinking with functions
+* Towards category theory
+  * Initial objects
+  * Generalized elements
+
+# From functions to morphisms
+* What is a category?
+  * All about morphisms
+  * Explain commuting diagrams somewhere here?
+  * Products
+  * Sums
+  * Exponents
+
+# Functors in category theory
+* Functors
+  * Endofunctors
+  
+# Algebra through functors
+* Algebra in a category
+  * Monoidal object
+  * Use this to motivate F-algebras
+	* Homomorphism
+	  * relate to classical concept of homomorphisms
+	  * some examples
+  
+# Datatypes through fixpoints
+* Recursive types in haskell as fixpoints of functors
+  * Initial algebra fixpoints
+  * Construction
+  * Catamorphisms
+  * Some examples of familiar datatypes described in this way
+  * How catamorphisms compute backwards
+
+# Writing foldr
+* Recovering `foldr`
+  
+# ???
+* Recommendations
+  * Category theory for programmers
+  * Ther are many category theory books
+  
+# Bonus: monoids in the category of endofunctors
+* monads are monoids in the category of endofunctors
+  * category of endofunctors
+	* natural transformations
+  * relate monoid example from before
+  * multiplication given by composition instead of $\times$
diff --git a/_layouts/.default.html.~undo-tree~ b/_layouts/.default.html.~undo-tree~
new file mode 100644
index 0000000..aaa653f
--- /dev/null
+++ b/_layouts/.default.html.~undo-tree~
@@ -0,0 +1,4 @@
+(undo-tree-save-format-version . 1)
+"b4678c7c50ca2382a4ee19802e15ad4b121d22a9"
+[nil current nil nil (25733 45126 379234 704000) 0 nil]
+nil
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..4c4f61b
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,92 @@
+with import <nixpkgs> {}; let
+
+  json-minify = (buildRubyGem {
+    gemName = "json-minify";
+    dependencies = [ rubyPackages.json ];
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "fd38ef93867332c2340aaf1b57335782ab5958fe6fb3ca7a8aba1469f0bf08ae";
+      type = "gem";
+    };
+    version = "0.0.3";
+  });
+
+  htmlcompressor = (buildRubyGem {
+    gemName = "htmlcompressor";
+    dependencies = [ ];
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "4630cf8ed46b563f0b49cc6028a3fe8c17a9067f2becd7c3a2aa5aaacefb1f9e";
+      type = "gem";
+    };
+    version = "0.4.0";
+  });
+
+  cssminify2 = (buildRubyGem {
+    gemName = "cssminify2";
+    dependencies = [ ];
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "e311cfced4ccfc55d27bf30520f7d11ed129bf04dcadd5a82e791a141e45b98c";
+      type = "gem";
+    };
+    version = "2.0.1";
+  });
+
+  jekyll-katex = (buildRubyGem {
+    gemName = "jekyll-katex";
+    dependencies = [ rubyPackages.execjs jekyll ];
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "ff16aced6a4577a76bf429c853a055ff6511a06f8fee06028adc26aaf28f58cd";
+      type = "gem";
+    };
+    version = "1.0.0";
+  });
+ 
+  jekyll-minifier = (buildRubyGem {
+    gemName = "jekyll-minifier";
+    dependencies = [ cssminify2 htmlcompressor rubyPackages.jekyll json-minify rubyPackages.uglifier ];
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "cd05bd9b2105f1dfd344397c480c17bea7d93871e239f5ca3949852ff1d938a3";
+      type = "gem";
+    };
+    version = "0.1.10";
+  });
+
+  jekyll-agda = (buildRubyGem {
+    gemName = "jekyll-agda";
+    dependencies = [ agda jekyll ];
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "fb2af6ac3ce9f11260b1c3d8e28075f23436577e5172e7defa029fb90e808fa3";
+      type = "gem";
+    };
+    version = "0.1.0";
+  });
+in
+mkShell {
+  packages = [
+    nodejs
+    (ruby.withPackages (ps: with ps; [
+      jekyll
+      jekyll-feed
+      jekyll-katex
+      jekyll-minifier
+      jekyll-agda
+    ]))
+  ];
+}