diff --git a/programs/data_decls.lily b/programs/data_decls.lily
new file mode 100644
index 0000000..85af0c1
--- /dev/null
+++ b/programs/data_decls.lily
@@ -0,0 +1,2 @@
+data Bool = { True, False }
+data IntList = { Nil, Cons(Int, IntList) }
diff --git a/programs/length.lily b/programs/length.lily
new file mode 100644
index 0000000..3463966
--- /dev/null
+++ b/programs/length.lily
@@ -0,0 +1,6 @@
+defn length l = {
+    case l of {
+        Nil -> { 0 }
+        Cons(x, xs) -> { 1 + length xs }
+    }
+}
diff --git a/programs/not.lily b/programs/not.lily
new file mode 100644
index 0000000..8676963
--- /dev/null
+++ b/programs/not.lily
@@ -0,0 +1,6 @@
+defn not b = {
+    case b of {
+        False -> { True }
+        True -> { False }
+    }
+}