diff --git a/config.json b/config.json
index ea518d2..8ad055d 100644
--- a/config.json
+++ b/config.json
@@ -606,6 +606,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "food-chain",
+        "name": "Food Chain",
+        "uuid": "18810489-b71e-4d1c-9f2d-e9ac28580fd4",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "knapsack",
         "name": "Knapsack",
diff --git a/exercises/practice/food-chain/.docs/instructions.md b/exercises/practice/food-chain/.docs/instructions.md
new file mode 100644
index 0000000..125820e
--- /dev/null
+++ b/exercises/practice/food-chain/.docs/instructions.md
@@ -0,0 +1,64 @@
+# Instructions
+
+Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'.
+
+While you could copy/paste the lyrics, or read them from a file, this problem is much more interesting if you approach it algorithmically.
+
+This is a [cumulative song][cumulative-song] of unknown origin.
+
+This is one of many common variants.
+
+```text
+I know an old lady who swallowed a fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a spider.
+It wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a bird.
+How absurd to swallow a bird!
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a cat.
+Imagine that, to swallow a cat!
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a dog.
+What a hog, to swallow a dog!
+She swallowed the dog to catch the cat.
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a goat.
+Just opened her throat and swallowed a goat!
+She swallowed the goat to catch the dog.
+She swallowed the dog to catch the cat.
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a cow.
+I don't know how she swallowed a cow!
+She swallowed the cow to catch the goat.
+She swallowed the goat to catch the dog.
+She swallowed the dog to catch the cat.
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a horse.
+She's dead, of course!
+```
+
+[cumulative-song]: https://en.wikipedia.org/wiki/Cumulative_song
diff --git a/exercises/practice/food-chain/.meta/config.json b/exercises/practice/food-chain/.meta/config.json
new file mode 100644
index 0000000..e5dc0ff
--- /dev/null
+++ b/exercises/practice/food-chain/.meta/config.json
@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "food-chain.sml"
+    ],
+    "test": [
+      "test.sml"
+    ],
+    "example": [
+      ".meta/example.sml"
+    ]
+  },
+  "blurb": "Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/There_Was_an_Old_Lady_Who_Swallowed_a_Fly"
+}
diff --git a/exercises/practice/food-chain/.meta/example.sml b/exercises/practice/food-chain/.meta/example.sml
new file mode 100644
index 0000000..8d225f3
--- /dev/null
+++ b/exercises/practice/food-chain/.meta/example.sml
@@ -0,0 +1,37 @@
+fun recite (startVerse: int, endVerse: int): string =
+  let
+    val animals = [ "", "fly", "spider", "bird", "cat", "dog", "goat", "cow", "horse" ]
+
+    val animal = List.nth (animals, startVerse)
+
+    val exclamations = [
+      "",
+      "I don't know why she swallowed the fly. Perhaps she'll die.",
+      "It wriggled and jiggled and tickled inside her.\n",
+      "How absurd to swallow a bird!\n",
+      "Imagine that, to swallow a cat!\n",
+      "What a hog, to swallow a dog!\n",
+      "Just opened her throat and swallowed a goat!\n",
+      "I don't know how she swallowed a cow!\n",
+      "She's dead, of course!"
+    ]
+
+    val exclamation = List.nth (exclamations, startVerse)
+
+    fun loop (index: int): string =
+      let
+        val current = List.nth (animals, index)
+
+        val previous = List.nth (animals, index - 1) ^ (if index = 3 then " that wriggled and jiggled and tickled inside her" else "")
+
+        val suffix = if index = 2 then List.nth (exclamations, 1) else loop (index - 1)
+      in
+        "She swallowed the " ^ current ^ " to catch the " ^ previous ^ ".\n" ^ suffix
+      end
+
+    val reasons = (if startVerse = 1 orelse startVerse = 8 then "" else loop(startVerse))
+
+    val suffix = if startVerse = endVerse then "" else "\n\n" ^ recite (startVerse + 1, endVerse)
+  in
+    "I know an old lady who swallowed a " ^ animal ^ ".\n" ^ exclamation ^ reasons ^ suffix
+  end
diff --git a/exercises/practice/food-chain/.meta/tests.toml b/exercises/practice/food-chain/.meta/tests.toml
new file mode 100644
index 0000000..30c5b98
--- /dev/null
+++ b/exercises/practice/food-chain/.meta/tests.toml
@@ -0,0 +1,40 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[751dce68-9412-496e-b6e8-855998c56166]
+description = "fly"
+
+[6c56f861-0c5e-4907-9a9d-b2efae389379]
+description = "spider"
+
+[3edf5f33-bef1-4e39-ae67-ca5eb79203fa]
+description = "bird"
+
+[e866a758-e1ff-400e-9f35-f27f28cc288f]
+description = "cat"
+
+[3f02c30e-496b-4b2a-8491-bc7e2953cafb]
+description = "dog"
+
+[4b3fd221-01ea-46e0-825b-5734634fbc59]
+description = "goat"
+
+[1b707da9-7001-4fac-941f-22ad9c7a65d4]
+description = "cow"
+
+[3cb10d46-ae4e-4d2c-9296-83c9ffc04cdc]
+description = "horse"
+
+[22b863d5-17e4-4d1e-93e4-617329a5c050]
+description = "multiple verses"
+
+[e626b32b-745c-4101-bcbd-3b13456893db]
+description = "full song"
diff --git a/exercises/practice/food-chain/food-chain.sml b/exercises/practice/food-chain/food-chain.sml
new file mode 100644
index 0000000..7dfed99
--- /dev/null
+++ b/exercises/practice/food-chain/food-chain.sml
@@ -0,0 +1,2 @@
+fun recite (startVerse: int, endVerse: int): string =
+  raise Fail "'recite' is not implemented"
diff --git a/exercises/practice/food-chain/test.sml b/exercises/practice/food-chain/test.sml
new file mode 100644
index 0000000..f19ede4
--- /dev/null
+++ b/exercises/practice/food-chain/test.sml
@@ -0,0 +1,188 @@
+(* version 1.0.0 *)
+
+use "testlib.sml";
+use "food-chain.sml";
+
+infixr |>
+fun x |> f = f x
+
+val testsuite =
+  describe "food-chain" [
+    test "fly"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (1, 1) |> Expect.equalTo expected
+      end),
+
+    test "spider"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a spider.\n\
+          \It wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (2, 2) |> Expect.equalTo expected
+      end),
+
+    test "bird"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a bird.\n\
+          \How absurd to swallow a bird!\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (3, 3) |> Expect.equalTo expected
+      end),
+
+    test "cat"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a cat.\n\
+          \Imagine that, to swallow a cat!\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (4, 4) |> Expect.equalTo expected
+      end),
+
+    test "dog"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a dog.\n\
+          \What a hog, to swallow a dog!\n\
+          \She swallowed the dog to catch the cat.\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (5, 5) |> Expect.equalTo expected
+      end),
+
+    test "goat"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a goat.\n\
+          \Just opened her throat and swallowed a goat!\n\
+          \She swallowed the goat to catch the dog.\n\
+          \She swallowed the dog to catch the cat.\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (6, 6) |> Expect.equalTo expected
+      end),
+
+    test "cow"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a cow.\n\
+          \I don't know how she swallowed a cow!\n\
+          \She swallowed the cow to catch the goat.\n\
+          \She swallowed the goat to catch the dog.\n\
+          \She swallowed the dog to catch the cat.\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (7, 7) |> Expect.equalTo expected
+      end),
+
+    test "horse"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a horse.\n\
+          \She's dead, of course!"
+      in
+        recite (8, 8) |> Expect.equalTo expected
+      end),
+
+    test "multiple verses"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a spider.\n\
+          \It wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a bird.\n\
+          \How absurd to swallow a bird!\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die."
+      in
+        recite (1, 3) |> Expect.equalTo expected
+      end),
+
+    test "full song"
+      (fn _ => let
+        val expected =
+          "I know an old lady who swallowed a fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a spider.\n\
+          \It wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a bird.\n\
+          \How absurd to swallow a bird!\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a cat.\n\
+          \Imagine that, to swallow a cat!\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a dog.\n\
+          \What a hog, to swallow a dog!\n\
+          \She swallowed the dog to catch the cat.\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a goat.\n\
+          \Just opened her throat and swallowed a goat!\n\
+          \She swallowed the goat to catch the dog.\n\
+          \She swallowed the dog to catch the cat.\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a cow.\n\
+          \I don't know how she swallowed a cow!\n\
+          \She swallowed the cow to catch the goat.\n\
+          \She swallowed the goat to catch the dog.\n\
+          \She swallowed the dog to catch the cat.\n\
+          \She swallowed the cat to catch the bird.\n\
+          \She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.\n\
+          \She swallowed the spider to catch the fly.\n\
+          \I don't know why she swallowed the fly. Perhaps she'll die.\n\
+          \\n\
+          \I know an old lady who swallowed a horse.\n\
+          \She's dead, of course!"
+      in
+        recite (1, 8) |> Expect.equalTo expected
+      end)
+  ]
+
+val _ = Test.run testsuite
diff --git a/exercises/practice/food-chain/testlib.sml b/exercises/practice/food-chain/testlib.sml
new file mode 100644
index 0000000..0c8370c
--- /dev/null
+++ b/exercises/practice/food-chain/testlib.sml
@@ -0,0 +1,160 @@
+structure Expect =
+struct
+  datatype expectation = Pass | Fail of string * string
+
+  local
+    fun failEq b a =
+      Fail ("Expected: " ^ b, "Got: " ^ a)
+    
+    fun failExn b a =
+      Fail ("Expected: " ^ b, "Raised: " ^ a)
+
+    fun exnName (e: exn): string = General.exnName e
+  in
+    fun truthy a =
+      if a
+      then Pass
+      else failEq "true" "false"
+
+    fun falsy a =
+      if a
+      then failEq "false" "true"
+      else Pass
+
+    fun equalTo b a = 
+      if a = b
+      then Pass
+      else failEq (PolyML.makestring b) (PolyML.makestring a)
+
+    fun nearTo delta b a =
+      if Real.abs (a - b) <= delta * Real.abs a orelse
+         Real.abs (a - b) <= delta * Real.abs b
+      then Pass
+      else failEq (Real.toString b ^ " +/- " ^ Real.toString delta) (Real.toString a)
+
+    fun anyError f =
+      (
+        f ();
+        failExn "an exception" "Nothing"
+      ) handle _ => Pass
+
+    fun error e f =
+      (
+        f ();
+        failExn (exnName e) "Nothing"
+      ) handle e' => if exnMessage e' = exnMessage e
+                     then Pass
+                     else failExn (exnMessage e) (exnMessage e')
+  end
+end
+
+structure TermColor =
+struct
+  datatype color = Red | Green | Yellow | Normal
+
+  fun f Red    = "\027[31m"
+    | f Green  = "\027[32m"
+    | f Yellow = "\027[33m"
+    | f Normal = "\027[0m"
+
+  fun colorize color s = (f color) ^ s ^ (f Normal)
+
+  val redit = colorize Red
+
+  val greenit = colorize Green
+
+  val yellowit = colorize Yellow
+end
+
+structure Test =
+struct
+  datatype testnode = TestGroup of string * testnode list
+                    | Test of string * (unit -> Expect.expectation)
+
+  local
+    datatype evaluation = Success of string
+                        | Failure of string * string * string
+                        | Error of string * string
+
+    fun indent n s = (implode (List.tabulate (n, fn _ => #" "))) ^ s
+
+    fun fmt indentlvl ev =
+      let
+        val check = TermColor.greenit "\226\156\148 " (* ✔ *)
+        val cross = TermColor.redit "\226\156\150 "   (* ✖ *)
+        val indentlvl = indentlvl * 2
+      in
+      case ev of
+        Success descr => indent indentlvl (check ^ descr)
+      | Failure (descr, exp, got) =>
+          String.concatWith "\n" [indent indentlvl (cross ^ descr),
+                                  indent (indentlvl + 2) exp,
+                                  indent (indentlvl + 2) got]
+      | Error (descr, reason) =>
+          String.concatWith "\n" [indent indentlvl (cross ^ descr),
+                                  indent (indentlvl + 2) (TermColor.redit reason)]
+      end
+
+    fun eval (TestGroup _) = raise Fail "Only a 'Test' can be evaluated"
+      | eval (Test (descr, thunk)) =
+          (
+            case thunk () of
+              Expect.Pass   => ((1, 0, 0), Success descr)
+            | Expect.Fail (s, s') => ((0, 1, 0), Failure (descr, s, s'))
+          )
+          handle e => ((0, 0, 1), Error (descr, "Unexpected error: " ^ exnMessage e))
+
+    fun flatten depth testnode =
+      let
+        fun sum (x, y, z) (a, b, c) = (x + a, y + b, z + c)
+
+        fun aux (t, (counter, acc)) =
+          let
+            val (counter', texts) = flatten (depth + 1) t
+          in
+            (sum counter' counter, texts :: acc)
+          end
+      in
+        case testnode of
+          TestGroup (descr, ts) =>
+            let
+              val (counter, texts) = foldr aux ((0, 0, 0), []) ts
+            in
+              (counter, (indent (depth * 2) descr) :: List.concat texts)
+            end
+        | Test _ =>
+            let
+              val (counter, evaluation) = eval testnode
+            in
+              (counter, [fmt depth evaluation])
+            end
+      end
+    
+    fun println s = print (s ^ "\n")
+  in
+    fun run suite =
+      let
+        val ((succeeded, failed, errored), texts) = flatten 0 suite
+
+        val summary = String.concatWith ", " [
+          TermColor.greenit ((Int.toString succeeded) ^ " passed"),
+          TermColor.redit ((Int.toString failed) ^ " failed"),
+          TermColor.redit ((Int.toString errored) ^ " errored"),
+          (Int.toString (succeeded + failed + errored)) ^ " total"
+        ]
+        
+        val status = if failed = 0 andalso errored = 0
+                     then OS.Process.success
+                     else OS.Process.failure
+
+      in
+        List.app println texts;
+        println "";
+        println ("Tests: " ^ summary);
+        OS.Process.exit status
+      end
+  end
+end
+
+fun describe description tests = Test.TestGroup (description, tests)
+fun test description thunk = Test.Test (description, thunk)