From 5b299b5b6271db734d835f4901986cc4aff65948 Mon Sep 17 00:00:00 2001
From: J R M <jwrmmine@protonmail.com>
Date: Fri, 30 Jan 2026 15:38:58 +0100
Subject: [PATCH 1/4] collatz

---
 .../collatz-conjecture/.docs/instructions.md  |  3 ++
 .../collatz-conjecture/.docs/introduction.md  | 28 ++++++++++++++
 .../collatz-conjecture/.meta/config.json      | 19 ++++++++++
 .../collatz-conjecture/.meta/example.nu       | 17 +++++++++
 .../collatz-conjecture/.meta/tests.toml       | 38 +++++++++++++++++++
 .../collatz-conjecture/collatz-conjecture.nu  |  3 ++
 .../practice/collatz-conjecture/tests.nu      | 18 +++++++++
 7 files changed, 126 insertions(+)
 create mode 100644 exercises/practice/collatz-conjecture/.docs/instructions.md
 create mode 100644 exercises/practice/collatz-conjecture/.docs/introduction.md
 create mode 100644 exercises/practice/collatz-conjecture/.meta/config.json
 create mode 100644 exercises/practice/collatz-conjecture/.meta/example.nu
 create mode 100644 exercises/practice/collatz-conjecture/.meta/tests.toml
 create mode 100644 exercises/practice/collatz-conjecture/collatz-conjecture.nu
 create mode 100644 exercises/practice/collatz-conjecture/tests.nu

diff --git a/exercises/practice/collatz-conjecture/.docs/instructions.md b/exercises/practice/collatz-conjecture/.docs/instructions.md
new file mode 100644
index 0000000..af332a8
--- /dev/null
+++ b/exercises/practice/collatz-conjecture/.docs/instructions.md
@@ -0,0 +1,3 @@
+# Instructions
+
+Given a positive integer, return the number of steps it takes to reach 1 according to the rules of the Collatz Conjecture.
diff --git a/exercises/practice/collatz-conjecture/.docs/introduction.md b/exercises/practice/collatz-conjecture/.docs/introduction.md
new file mode 100644
index 0000000..c35bdeb
--- /dev/null
+++ b/exercises/practice/collatz-conjecture/.docs/introduction.md
@@ -0,0 +1,28 @@
+# Introduction
+
+One evening, you stumbled upon an old notebook filled with cryptic scribbles, as though someone had been obsessively chasing an idea.
+On one page, a single question stood out: **Can every number find its way to 1?**
+It was tied to something called the **Collatz Conjecture**, a puzzle that has baffled thinkers for decades.
+
+The rules were deceptively simple.
+Pick any positive integer.
+
+- If it's even, divide it by 2.
+- If it's odd, multiply it by 3 and add 1.
+
+Then, repeat these steps with the result, continuing indefinitely.
+
+Curious, you picked number 12 to test and began the journey:
+
+12 ➜ 6 ➜ 3 ➜ 10 ➜ 5 ➜ 16 ➜ 8 ➜ 4 ➜ 2 ➜ 1
+
+Counting from the second number (6), it took 9 steps to reach 1, and each time the rules repeated, the number kept changing.
+At first, the sequence seemed unpredictable — jumping up, down, and all over.
+Yet, the conjecture claims that no matter the starting number, we'll always end at 1.
+
+It was fascinating, but also puzzling.
+Why does this always seem to work?
+Could there be a number where the process breaks down, looping forever or escaping into infinity?
+The notebook suggested solving this could reveal something profound — and with it, fame, [fortune][collatz-prize], and a place in history awaits whoever could unlock its secrets.
+
+[collatz-prize]: https://mathprize.net/posts/collatz-conjecture/
diff --git a/exercises/practice/collatz-conjecture/.meta/config.json b/exercises/practice/collatz-conjecture/.meta/config.json
new file mode 100644
index 0000000..1b6fb58
--- /dev/null
+++ b/exercises/practice/collatz-conjecture/.meta/config.json
@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "quintuple-mallard"
+  ],
+  "files": {
+    "solution": [
+      "collatz-conjecture.nu"
+    ],
+    "test": [
+      "tests.nu"
+    ],
+    "example": [
+      ".meta/example.nu"
+    ]
+  },
+  "blurb": "Calculate the number of steps to reach 1 using the Collatz conjecture.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Collatz_conjecture"
+}
diff --git a/exercises/practice/collatz-conjecture/.meta/example.nu b/exercises/practice/collatz-conjecture/.meta/example.nu
new file mode 100644
index 0000000..f9c1887
--- /dev/null
+++ b/exercises/practice/collatz-conjecture/.meta/example.nu
@@ -0,0 +1,17 @@
+export def steps [number] {
+    if $number <= 0 {
+        error make {msg: "Only positive integers are allowed"}
+    }
+    mut number = $number
+    mut steps = 0
+    while $number != 1 {
+        $steps += 1
+        if ($number mod 2) == 1 {
+            $number *= 3
+            $number += 1
+        } else {
+            $number /= 2
+        }
+    }
+    $steps
+}
diff --git a/exercises/practice/collatz-conjecture/.meta/tests.toml b/exercises/practice/collatz-conjecture/.meta/tests.toml
new file mode 100644
index 0000000..cc34e16
--- /dev/null
+++ b/exercises/practice/collatz-conjecture/.meta/tests.toml
@@ -0,0 +1,38 @@
+# 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.
+
+[540a3d51-e7a6-47a5-92a3-4ad1838f0bfd]
+description = "zero steps for one"
+
+[3d76a0a6-ea84-444a-821a-f7857c2c1859]
+description = "divide if even"
+
+[754dea81-123c-429e-b8bc-db20b05a87b9]
+description = "even and odd steps"
+
+[ecfd0210-6f85-44f6-8280-f65534892ff6]
+description = "large number of even and odd steps"
+
+[7d4750e6-def9-4b86-aec7-9f7eb44f95a3]
+description = "zero is an error"
+include = false
+
+[2187673d-77d6-4543-975e-66df6c50e2da]
+description = "zero is an error"
+reimplements = "7d4750e6-def9-4b86-aec7-9f7eb44f95a3"
+
+[c6c795bf-a288-45e9-86a1-841359ad426d]
+description = "negative value is an error"
+include = false
+
+[ec11f479-56bc-47fd-a434-bcd7a31a7a2e]
+description = "negative value is an error"
+reimplements = "c6c795bf-a288-45e9-86a1-841359ad426d"
diff --git a/exercises/practice/collatz-conjecture/collatz-conjecture.nu b/exercises/practice/collatz-conjecture/collatz-conjecture.nu
new file mode 100644
index 0000000..86b2f77
--- /dev/null
+++ b/exercises/practice/collatz-conjecture/collatz-conjecture.nu
@@ -0,0 +1,3 @@
+export def steps [number] {
+    error make {msg: "Please implement steps"}
+}
diff --git a/exercises/practice/collatz-conjecture/tests.nu b/exercises/practice/collatz-conjecture/tests.nu
new file mode 100644
index 0000000..a986b00
--- /dev/null
+++ b/exercises/practice/collatz-conjecture/tests.nu
@@ -0,0 +1,18 @@
+use collatz-conjecture.nu steps
+use std/assert
+# zero steps for one
+assert equal (steps 1) 0
+# divide if even
+assert equal (steps 16) 4
+# even and odd steps
+assert equal (steps 12) 9
+# large number of even and odd steps
+assert equal (steps 1000000) 152
+# zero is an error
+assert equal (try { steps 0 } catch {|e|
+  $e.msg
+}) "Only positive integers are allowed"
+# negative value is an error
+assert equal (try { steps (-15) } catch {|e|
+  $e.msg
+})  "Only positive integers are allowed"

From 2edb6e7ae0251d3d98e3e86471cb282507950980 Mon Sep 17 00:00:00 2001
From: J R M <jwrmmine@protonmail.com>
Date: Fri, 30 Jan 2026 15:39:50 +0100
Subject: [PATCH 2/4] difficulty

---
 config.json                                   | 10 +++-
 .../simple-cipher/.docs/instructions.md       | 40 ++++++++++++++++
 .../practice/simple-cipher/.meta/config.json  | 19 ++++++++
 .../practice/simple-cipher/.meta/example.nu   |  0
 .../practice/simple-cipher/.meta/tests.toml   | 46 +++++++++++++++++++
 exercises/practice/simple-cipher/TODO         |  1 +
 .../practice/simple-cipher/simple-cipher.nu   | 13 ++++++
 exercises/practice/simple-cipher/tests.nu     |  0
 8 files changed, 128 insertions(+), 1 deletion(-)
 create mode 100644 exercises/practice/simple-cipher/.docs/instructions.md
 create mode 100644 exercises/practice/simple-cipher/.meta/config.json
 create mode 100644 exercises/practice/simple-cipher/.meta/example.nu
 create mode 100644 exercises/practice/simple-cipher/.meta/tests.toml
 create mode 100644 exercises/practice/simple-cipher/TODO
 create mode 100644 exercises/practice/simple-cipher/simple-cipher.nu
 create mode 100644 exercises/practice/simple-cipher/tests.nu

diff --git a/config.json b/config.json
index 7ed89e4..a550e73 100644
--- a/config.json
+++ b/config.json
@@ -117,6 +117,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 6
+      },
+      {
+        "slug": "collatz-conjecture",
+        "name": "Collatz Conjecture",
+        "uuid": "dc42f98e-d0fe-4c0f-ab4d-1954cf839ea8",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
       }
     ]
   },
@@ -130,4 +138,4 @@
     "typing/static",
     "used_for/scripts"
   ]
-}
+}
\ No newline at end of file
diff --git a/exercises/practice/simple-cipher/.docs/instructions.md b/exercises/practice/simple-cipher/.docs/instructions.md
new file mode 100644
index 0000000..afd0b57
--- /dev/null
+++ b/exercises/practice/simple-cipher/.docs/instructions.md
@@ -0,0 +1,40 @@
+# Instructions
+
+Create an implementation of the [Vigenère cipher][wiki].
+The Vigenère cipher is a simple substitution cipher.
+
+## Cipher terminology
+
+A cipher is an algorithm used to encrypt, or encode, a string.
+The unencrypted string is called the _plaintext_ and the encrypted string is called the _ciphertext_.
+Converting plaintext to ciphertext is called _encoding_ while the reverse is called _decoding_.
+
+In a _substitution cipher_, each plaintext letter is replaced with a ciphertext letter which is computed with the help of a _key_.
+(Note, it is possible for replacement letter to be the same as the original letter.)
+
+## Encoding details
+
+In this cipher, the key is a series of lowercase letters, such as `"abcd"`.
+Each letter of the plaintext is _shifted_ or _rotated_ by a distance based on a corresponding letter in the key.
+An `"a"` in the key means a shift of 0 (that is, no shift).
+A `"b"` in the key means a shift of 1.
+A `"c"` in the key means a shift of 2, and so on.
+
+The first letter of the plaintext uses the first letter of the key, the second letter of the plaintext uses the second letter of the key and so on.
+If you run out of letters in the key before you run out of letters in the plaintext, start over from the start of the key again.
+
+If the key only contains one letter, such as `"dddddd"`, then all letters of the plaintext are shifted by the same amount (three in this example), which would make this the same as a rotational cipher or shift cipher (sometimes called a Caesar cipher).
+For example, the plaintext `"iamapandabear"` would become `"ldpdsdqgdehdu"`.
+
+If the key only contains the letter `"a"` (one or more times), the shift distance is zero and the ciphertext is the same as the plaintext.
+
+Usually the key is more complicated than that, though!
+If the key is `"abcd"` then letters of the plaintext would be shifted by a distance of 0, 1, 2, and 3.
+If the plaintext is `"hello"`, we need 5 shifts so the key would wrap around, giving shift distances of 0, 1, 2, 3, and 0.
+Applying those shifts to the letters of `"hello"` we get `"hfnoo"`.
+
+## Random keys
+
+If no key is provided, generate a key which consists of at least 100 random lowercase letters from the Latin alphabet.
+
+[wiki]: https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher
diff --git a/exercises/practice/simple-cipher/.meta/config.json b/exercises/practice/simple-cipher/.meta/config.json
new file mode 100644
index 0000000..bbb27b7
--- /dev/null
+++ b/exercises/practice/simple-cipher/.meta/config.json
@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "quintuple-mallard"
+  ],
+  "files": {
+    "solution": [
+      "simple-cipher.nu"
+    ],
+    "test": [
+      "tests.nu"
+    ],
+    "example": [
+      ".meta/example.nu"
+    ]
+  },
+  "blurb": "Implement the Vigenère cipher, a simple substitution cipher.",
+  "source": "Substitution Cipher at Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Substitution_cipher"
+}
diff --git a/exercises/practice/simple-cipher/.meta/example.nu b/exercises/practice/simple-cipher/.meta/example.nu
new file mode 100644
index 0000000..e69de29
diff --git a/exercises/practice/simple-cipher/.meta/tests.toml b/exercises/practice/simple-cipher/.meta/tests.toml
new file mode 100644
index 0000000..77e6571
--- /dev/null
+++ b/exercises/practice/simple-cipher/.meta/tests.toml
@@ -0,0 +1,46 @@
+# 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.
+
+[b8bdfbe1-bea3-41bb-a999-b41403f2b15d]
+description = "Random key cipher -> Can encode"
+
+[3dff7f36-75db-46b4-ab70-644b3f38b81c]
+description = "Random key cipher -> Can decode"
+
+[8143c684-6df6-46ba-bd1f-dea8fcb5d265]
+description = "Random key cipher -> Is reversible. I.e., if you apply decode in a encoded result, you must see the same plaintext encode parameter as a result of the decode method"
+
+[defc0050-e87d-4840-85e4-51a1ab9dd6aa]
+description = "Random key cipher -> Key is made only of lowercase letters"
+
+[565e5158-5b3b-41dd-b99d-33b9f413c39f]
+description = "Substitution cipher -> Can encode"
+
+[d44e4f6a-b8af-4e90-9d08-fd407e31e67b]
+description = "Substitution cipher -> Can decode"
+
+[70a16473-7339-43df-902d-93408c69e9d1]
+description = "Substitution cipher -> Is reversible. I.e., if you apply decode in a encoded result, you must see the same plaintext encode parameter as a result of the decode method"
+
+[69a1458b-92a6-433a-a02d-7beac3ea91f9]
+description = "Substitution cipher -> Can double shift encode"
+
+[21d207c1-98de-40aa-994f-86197ae230fb]
+description = "Substitution cipher -> Can wrap on encode"
+
+[a3d7a4d7-24a9-4de6-bdc4-a6614ced0cb3]
+description = "Substitution cipher -> Can wrap on decode"
+
+[e31c9b8c-8eb6-45c9-a4b5-8344a36b9641]
+description = "Substitution cipher -> Can encode messages longer than the key"
+
+[93cfaae0-17da-4627-9a04-d6d1e1be52e3]
+description = "Substitution cipher -> Can decode messages longer than the key"
diff --git a/exercises/practice/simple-cipher/TODO b/exercises/practice/simple-cipher/TODO
new file mode 100644
index 0000000..cf56e8e
--- /dev/null
+++ b/exercises/practice/simple-cipher/TODO
@@ -0,0 +1 @@
+remove this file when implementation is done
diff --git a/exercises/practice/simple-cipher/simple-cipher.nu b/exercises/practice/simple-cipher/simple-cipher.nu
new file mode 100644
index 0000000..3f792f6
--- /dev/null
+++ b/exercises/practice/simple-cipher/simple-cipher.nu
@@ -0,0 +1,13 @@
+def caesar_cipher [text, shift] {
+    text | split chars | each {|c|
+    if ($c =~ "[A-Z]") {
+      char --integer  (((($c | encode hex | into int --radix 16) + shift) - ('A'| encode hex | into int --radix 16)) mod 26 + ('A'| encode hex | into int --radix 16));
+    
+    } else if ($c =~ "[a-z]") {
+      char --integer  (((($c | encode hex | into int --radix 16) + shift) - ('a'| encode hex | into int --radix 16)) mod 26 + ('a'| encode hex | into int --radix 16));
+    
+    } else {
+      $c
+    }
+  } | str join
+}
diff --git a/exercises/practice/simple-cipher/tests.nu b/exercises/practice/simple-cipher/tests.nu
new file mode 100644
index 0000000..e69de29

From af424b112ef3d3e0d9a3ac32e8468f6f670c95bb Mon Sep 17 00:00:00 2001
From: J R M <jwrmmine@protonmail.com>
Date: Fri, 30 Jan 2026 16:42:27 +0100
Subject: [PATCH 3/4] configlet fmt

---
 config.json                                              | 2 +-
 exercises/practice/resistor-color-duo/.meta/config.json  | 3 +--
 exercises/practice/resistor-color-trio/.meta/config.json | 3 +--
 exercises/practice/resistor-color/.meta/config.json      | 3 +--
 exercises/practice/strain/.meta/config.json              | 3 +--
 5 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/config.json b/config.json
index a550e73..8932b17 100644
--- a/config.json
+++ b/config.json
@@ -138,4 +138,4 @@
     "typing/static",
     "used_for/scripts"
   ]
-}
\ No newline at end of file
+}
diff --git a/exercises/practice/resistor-color-duo/.meta/config.json b/exercises/practice/resistor-color-duo/.meta/config.json
index 04c0bd5..7b53b87 100644
--- a/exercises/practice/resistor-color-duo/.meta/config.json
+++ b/exercises/practice/resistor-color-duo/.meta/config.json
@@ -15,6 +15,5 @@
   },
   "blurb": "Convert color codes, as used on resistors, to a numeric value.",
   "source": "Maud de Vries, Erik Schierboom",
-  "source_url": "https://github.com/exercism/problem-specifications/issues/1464",
-  "difficulty": 2
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1464"
 }
diff --git a/exercises/practice/resistor-color-trio/.meta/config.json b/exercises/practice/resistor-color-trio/.meta/config.json
index 44143a1..53e3554 100644
--- a/exercises/practice/resistor-color-trio/.meta/config.json
+++ b/exercises/practice/resistor-color-trio/.meta/config.json
@@ -15,6 +15,5 @@
   },
   "blurb": "Convert color codes, as used on resistors, to a human-readable label.",
   "source": "Maud de Vries, Erik Schierboom",
-  "source_url": "https://github.com/exercism/problem-specifications/issues/1549",
-  "difficulty": 4
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1549"
 }
diff --git a/exercises/practice/resistor-color/.meta/config.json b/exercises/practice/resistor-color/.meta/config.json
index 914c584..db31a4a 100644
--- a/exercises/practice/resistor-color/.meta/config.json
+++ b/exercises/practice/resistor-color/.meta/config.json
@@ -15,6 +15,5 @@
   },
   "blurb": "Convert a resistor band's color to its numeric representation.",
   "source": "Maud de Vries, Erik Schierboom",
-  "source_url": "https://github.com/exercism/problem-specifications/issues/1458",
-  "difficulty": 1
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1458"
 }
diff --git a/exercises/practice/strain/.meta/config.json b/exercises/practice/strain/.meta/config.json
index 9f3cf35..55616ed 100644
--- a/exercises/practice/strain/.meta/config.json
+++ b/exercises/practice/strain/.meta/config.json
@@ -15,6 +15,5 @@
   },
   "blurb": "Implement the `keep` and `discard` operation on collections.",
   "source": "Conversation with James Edward Gray II",
-  "source_url": "http://graysoftinc.com/",
-  "difficulty": 2
+  "source_url": "http://graysoftinc.com/"
 }

From 3767d64c8634e087c082079b821fee94c2787ca6 Mon Sep 17 00:00:00 2001
From: J R M <jwrmmine@protonmail.com>
Date: Fri, 30 Jan 2026 16:45:00 +0100
Subject: [PATCH 4/4] oops

---
 .../simple-cipher/.docs/instructions.md       | 40 ----------------
 .../practice/simple-cipher/.meta/config.json  | 19 --------
 .../practice/simple-cipher/.meta/example.nu   |  0
 .../practice/simple-cipher/.meta/tests.toml   | 46 -------------------
 exercises/practice/simple-cipher/TODO         |  1 -
 .../practice/simple-cipher/simple-cipher.nu   | 13 ------
 exercises/practice/simple-cipher/tests.nu     |  0
 7 files changed, 119 deletions(-)
 delete mode 100644 exercises/practice/simple-cipher/.docs/instructions.md
 delete mode 100644 exercises/practice/simple-cipher/.meta/config.json
 delete mode 100644 exercises/practice/simple-cipher/.meta/example.nu
 delete mode 100644 exercises/practice/simple-cipher/.meta/tests.toml
 delete mode 100644 exercises/practice/simple-cipher/TODO
 delete mode 100644 exercises/practice/simple-cipher/simple-cipher.nu
 delete mode 100644 exercises/practice/simple-cipher/tests.nu

diff --git a/exercises/practice/simple-cipher/.docs/instructions.md b/exercises/practice/simple-cipher/.docs/instructions.md
deleted file mode 100644
index afd0b57..0000000
--- a/exercises/practice/simple-cipher/.docs/instructions.md
+++ /dev/null
@@ -1,40 +0,0 @@
-# Instructions
-
-Create an implementation of the [Vigenère cipher][wiki].
-The Vigenère cipher is a simple substitution cipher.
-
-## Cipher terminology
-
-A cipher is an algorithm used to encrypt, or encode, a string.
-The unencrypted string is called the _plaintext_ and the encrypted string is called the _ciphertext_.
-Converting plaintext to ciphertext is called _encoding_ while the reverse is called _decoding_.
-
-In a _substitution cipher_, each plaintext letter is replaced with a ciphertext letter which is computed with the help of a _key_.
-(Note, it is possible for replacement letter to be the same as the original letter.)
-
-## Encoding details
-
-In this cipher, the key is a series of lowercase letters, such as `"abcd"`.
-Each letter of the plaintext is _shifted_ or _rotated_ by a distance based on a corresponding letter in the key.
-An `"a"` in the key means a shift of 0 (that is, no shift).
-A `"b"` in the key means a shift of 1.
-A `"c"` in the key means a shift of 2, and so on.
-
-The first letter of the plaintext uses the first letter of the key, the second letter of the plaintext uses the second letter of the key and so on.
-If you run out of letters in the key before you run out of letters in the plaintext, start over from the start of the key again.
-
-If the key only contains one letter, such as `"dddddd"`, then all letters of the plaintext are shifted by the same amount (three in this example), which would make this the same as a rotational cipher or shift cipher (sometimes called a Caesar cipher).
-For example, the plaintext `"iamapandabear"` would become `"ldpdsdqgdehdu"`.
-
-If the key only contains the letter `"a"` (one or more times), the shift distance is zero and the ciphertext is the same as the plaintext.
-
-Usually the key is more complicated than that, though!
-If the key is `"abcd"` then letters of the plaintext would be shifted by a distance of 0, 1, 2, and 3.
-If the plaintext is `"hello"`, we need 5 shifts so the key would wrap around, giving shift distances of 0, 1, 2, 3, and 0.
-Applying those shifts to the letters of `"hello"` we get `"hfnoo"`.
-
-## Random keys
-
-If no key is provided, generate a key which consists of at least 100 random lowercase letters from the Latin alphabet.
-
-[wiki]: https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher
diff --git a/exercises/practice/simple-cipher/.meta/config.json b/exercises/practice/simple-cipher/.meta/config.json
deleted file mode 100644
index bbb27b7..0000000
--- a/exercises/practice/simple-cipher/.meta/config.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-  "authors": [
-    "quintuple-mallard"
-  ],
-  "files": {
-    "solution": [
-      "simple-cipher.nu"
-    ],
-    "test": [
-      "tests.nu"
-    ],
-    "example": [
-      ".meta/example.nu"
-    ]
-  },
-  "blurb": "Implement the Vigenère cipher, a simple substitution cipher.",
-  "source": "Substitution Cipher at Wikipedia",
-  "source_url": "https://en.wikipedia.org/wiki/Substitution_cipher"
-}
diff --git a/exercises/practice/simple-cipher/.meta/example.nu b/exercises/practice/simple-cipher/.meta/example.nu
deleted file mode 100644
index e69de29..0000000
diff --git a/exercises/practice/simple-cipher/.meta/tests.toml b/exercises/practice/simple-cipher/.meta/tests.toml
deleted file mode 100644
index 77e6571..0000000
--- a/exercises/practice/simple-cipher/.meta/tests.toml
+++ /dev/null
@@ -1,46 +0,0 @@
-# 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.
-
-[b8bdfbe1-bea3-41bb-a999-b41403f2b15d]
-description = "Random key cipher -> Can encode"
-
-[3dff7f36-75db-46b4-ab70-644b3f38b81c]
-description = "Random key cipher -> Can decode"
-
-[8143c684-6df6-46ba-bd1f-dea8fcb5d265]
-description = "Random key cipher -> Is reversible. I.e., if you apply decode in a encoded result, you must see the same plaintext encode parameter as a result of the decode method"
-
-[defc0050-e87d-4840-85e4-51a1ab9dd6aa]
-description = "Random key cipher -> Key is made only of lowercase letters"
-
-[565e5158-5b3b-41dd-b99d-33b9f413c39f]
-description = "Substitution cipher -> Can encode"
-
-[d44e4f6a-b8af-4e90-9d08-fd407e31e67b]
-description = "Substitution cipher -> Can decode"
-
-[70a16473-7339-43df-902d-93408c69e9d1]
-description = "Substitution cipher -> Is reversible. I.e., if you apply decode in a encoded result, you must see the same plaintext encode parameter as a result of the decode method"
-
-[69a1458b-92a6-433a-a02d-7beac3ea91f9]
-description = "Substitution cipher -> Can double shift encode"
-
-[21d207c1-98de-40aa-994f-86197ae230fb]
-description = "Substitution cipher -> Can wrap on encode"
-
-[a3d7a4d7-24a9-4de6-bdc4-a6614ced0cb3]
-description = "Substitution cipher -> Can wrap on decode"
-
-[e31c9b8c-8eb6-45c9-a4b5-8344a36b9641]
-description = "Substitution cipher -> Can encode messages longer than the key"
-
-[93cfaae0-17da-4627-9a04-d6d1e1be52e3]
-description = "Substitution cipher -> Can decode messages longer than the key"
diff --git a/exercises/practice/simple-cipher/TODO b/exercises/practice/simple-cipher/TODO
deleted file mode 100644
index cf56e8e..0000000
--- a/exercises/practice/simple-cipher/TODO
+++ /dev/null
@@ -1 +0,0 @@
-remove this file when implementation is done
diff --git a/exercises/practice/simple-cipher/simple-cipher.nu b/exercises/practice/simple-cipher/simple-cipher.nu
deleted file mode 100644
index 3f792f6..0000000
--- a/exercises/practice/simple-cipher/simple-cipher.nu
+++ /dev/null
@@ -1,13 +0,0 @@
-def caesar_cipher [text, shift] {
-    text | split chars | each {|c|
-    if ($c =~ "[A-Z]") {
-      char --integer  (((($c | encode hex | into int --radix 16) + shift) - ('A'| encode hex | into int --radix 16)) mod 26 + ('A'| encode hex | into int --radix 16));
-    
-    } else if ($c =~ "[a-z]") {
-      char --integer  (((($c | encode hex | into int --radix 16) + shift) - ('a'| encode hex | into int --radix 16)) mod 26 + ('a'| encode hex | into int --radix 16));
-    
-    } else {
-      $c
-    }
-  } | str join
-}
diff --git a/exercises/practice/simple-cipher/tests.nu b/exercises/practice/simple-cipher/tests.nu
deleted file mode 100644
index e69de29..0000000