diff --git a/exercises/practice/acronym/.meta/acronym.ys b/exercises/practice/acronym/.meta/acronym.ys
index 4cfcb63..cb0bb94 100644
--- a/exercises/practice/acronym/.meta/acronym.ys
+++ b/exercises/practice/acronym/.meta/acronym.ys
@@ -1,6 +1,5 @@
 !yamlscript/v0
 
 defn abbreviate(phrase):
-  uc(phrase):
-    .re-seq(/[A-Z']+/)
+  uc(phrase).re-seq(/[A-Z']+/)
     .map(first):join
diff --git a/exercises/practice/allergies/.meta/allergies.ys b/exercises/practice/allergies/.meta/allergies.ys
index cce79f1..6852a78 100644
--- a/exercises/practice/allergies/.meta/allergies.ys
+++ b/exercises/practice/allergies/.meta/allergies.ys
@@ -1,20 +1,9 @@
 !yamlscript/v0
 
-allergen-map =:
-  zipmap _ range()::
-  - eggs
-  - peanuts
-  - shellfish
-  - strawberries
-  - tomatoes
-  - chocolate
-  - pollen
-  - cats
-
 defn allergic-to(item score):
-  bit-test score: allergen-map.$item
+  list-allergens(score).has?(item)
 
 defn list-allergens(score):
-  keep _ allergen-map:
-    fn([allergen num]):
-      bit-test(score num) &&& allergen
+  (0 .. 7).filter(P(bit-test score))
+    .map(qw(eggs peanuts shellfish strawberries
+            tomatoes chocolate pollen cats))
diff --git a/exercises/practice/anagram/.meta/anagram.ys b/exercises/practice/anagram/.meta/anagram.ys
index 5b3c4ec..ef17ba8 100644
--- a/exercises/practice/anagram/.meta/anagram.ys
+++ b/exercises/practice/anagram/.meta/anagram.ys
@@ -2,7 +2,7 @@
 
 defn find-anagrams(subject candidates):
   filter _ candidates:
-    partial _ subject:
+    P _ subject:
       fn(*words):
         word1 word2 =: words.map(lc)
         word1 != word2 &&:
diff --git a/exercises/practice/bank-account/.meta/bank-account.ys b/exercises/practice/bank-account/.meta/bank-account.ys
index d7b446a..21e363a 100644
--- a/exercises/practice/bank-account/.meta/bank-account.ys
+++ b/exercises/practice/bank-account/.meta/bank-account.ys
@@ -1,50 +1,28 @@
 !yamlscript/v0
 
-account =: atom(nil)
+closed =: 'closed'
+closed? =: P(== closed)
 
 defn reset-test-state():
-  reset! account: nil
 
 defn bank-account(operations):
-  last:
-    for operation operations:
-      operation
-        .operation
-        .str('do-' _)
-        .call(operation)
-
-defn- do-open(op):
-  when deref(account):
-    die: 'account already open'
-  reset! account: 0
-
-defn- do-close(op):
-  when-not deref(account):
-    die: 'account not open'
-  reset! account: nil
-
-defn- do-balance(op):
-  balance =: deref(account)
-  if-not balance:
-    die: 'account not open'
-    else: balance
-
-defn- do-deposit(op):
-  when-not deref(account):
-    die: 'account not open'
-  swap! account +: op:get-amount
-
-defn- do-withdraw(op):
-  balance =: deref(account)
-  when-not balance:
-    die: 'account not open'
-  amount =: op:get-amount
-  when amount > balance:
-    die: 'amount must be less than balance'
-  swap! account -: amount
-
-defn- get-amount(op):
-  amount =: op.amount
-  if amount < 0:
-    die: 'amount must be greater than 0'
-    else: amount
+  reduce _ closed operations:
+    fn(bal op):
+      case op.operation:
+        -'open':
+          if closed?(bal): 0, die('account already open')
+        -'close':
+          if closed?(bal): die('account not open'), closed
+        -'balance':
+          if closed?(bal): die('account not open'), bal
+        -'deposit':
+          cond:
+            closed?(bal): die('account not open')
+            op.amount <= 0: die('amount must be greater than 0')
+            else: bal + op.amount
+        -'withdraw':
+          cond:
+            closed?(bal): die('account not open')
+            op.amount <= 0: die('amount must be greater than 0')
+            op.amount > bal: die('amount must be less than balance')
+            else: bal - op.amount
diff --git a/exercises/practice/binary-search/.meta/binary-search.ys b/exercises/practice/binary-search/.meta/binary-search.ys
index cb3baf9..e2efa5b 100644
--- a/exercises/practice/binary-search/.meta/binary-search.ys
+++ b/exercises/practice/binary-search/.meta/binary-search.ys
@@ -1,13 +1,9 @@
 !yamlscript/v0
 
 defn find(array value):
- loop low 0, high array.--:
-   when low > high:
-     die: 'value not in array'
-   mid =: (high + low).quot(2)
-   item =: array.$mid
-
-   cond:
-     value == item : mid
-     value <  item : recur(low mid.--)
-     else          : recur(mid.++ high)
+  when array.#.!: die('value not in array')
+  mid =: array.#.--.quot(2)
+  case compare(array.$mid value):
+    0: mid
+    1: find(take(mid array) value)
+    -1: find(drop(mid.++ array) value) + mid.++
diff --git a/exercises/practice/circular-buffer/.meta/circular-buffer.ys b/exercises/practice/circular-buffer/.meta/circular-buffer.ys
index a69b82a..c464b44 100644
--- a/exercises/practice/circular-buffer/.meta/circular-buffer.ys
+++ b/exercises/practice/circular-buffer/.meta/circular-buffer.ys
@@ -1,7 +1,7 @@
 !yamlscript/v0
 
 defn run(capacity operations):
-  buffer =: M(:B V(capacity * [nil]), :P 0)
+  buffer =: -{:B V(capacity * [nil]), :P 0}
   reduce _ buffer operations:
     fn(buffer op):
       op item pass want =:
@@ -10,14 +10,14 @@ defn run(capacity operations):
       args =:
         condp eq op:
           -'clear'     : -[buffer]
-          -'read'      : L(buffer pass want)
-          -'write'     : L(buffer pass item)
-          -'overwrite' : L(buffer pass item)
+          -'read'      : -[buffer pass want]
+          -'write'     : -[buffer pass item]
+          -'overwrite' : -[buffer pass item]
       value("op-$op"): args*
   =>: -{}
 
 defn op-clear(buffer):
-  M: :B V(buffer.B.# * [nil]) :P 0
+  hash-map: :B V(buffer.B.# * [nil]) :P 0
 
 defn op-read(buffer pass want):
   cell =: buffer.B.nth(buffer.P)
@@ -26,8 +26,9 @@ defn op-read(buffer pass want):
       die: S("Can't read:\ " buffer)
     when cell != want:
       die: "Bad read:\ $cell != $want ($buffer)"
-  M: :B update-in(buffer.B [buffer.P] constantly(nil))
-     :P (buffer.P.++ % buffer.B.#)
+  hash-map:
+    :B update-in(buffer.B [buffer.P] constantly(nil))
+    :P (buffer.P.++ % buffer.B.#)
 
 defn op-write(buffer pass item):
   B P =: buffer.slice(q(B P))
diff --git a/exercises/practice/eliuds-eggs/.meta/eliuds-eggs.ys b/exercises/practice/eliuds-eggs/.meta/eliuds-eggs.ys
index e2e7993..9ef5cbe 100644
--- a/exercises/practice/eliuds-eggs/.meta/eliuds-eggs.ys
+++ b/exercises/practice/eliuds-eggs/.meta/eliuds-eggs.ys
@@ -1,7 +1,4 @@
 !yamlscript/v0
 
 defn egg-count(number):
-  loop num number, eggs 0:
-    if num > 0:
-      recur: quot(num 2), eggs.add(num % 2)
-      else: eggs
+  len: P(bit-test number).filter(0 .. 31)
diff --git a/exercises/practice/etl/.meta/etl.ys b/exercises/practice/etl/.meta/etl.ys
index 47d15cd..e725c30 100644
--- a/exercises/practice/etl/.meta/etl.ys
+++ b/exercises/practice/etl/.meta/etl.ys
@@ -3,4 +3,4 @@
 defn transform(legacy):
   into {}:
     for [score letters] legacy, letter letters:
-      V: lc(letter) score:N
+      -[lc(letter) score:N]
diff --git a/exercises/practice/grains/.meta/grains.ys b/exercises/practice/grains/.meta/grains.ys
index d5760ba..fabc7ae 100644
--- a/exercises/practice/grains/.meta/grains.ys
+++ b/exercises/practice/grains/.meta/grains.ys
@@ -3,5 +3,4 @@
 defn square(square):
   (1 <= square <= 64) |||:
     die: 'square must be between 1 and 64'
-
-  pow 2: square - 1
+  2 **: square.--
diff --git a/exercises/practice/hamming/.meta/hamming.ys b/exercises/practice/hamming/.meta/hamming.ys
index 6ba3c67..1878c97 100644
--- a/exercises/practice/hamming/.meta/hamming.ys
+++ b/exercises/practice/hamming/.meta/hamming.ys
@@ -3,5 +3,4 @@
 defn distance(strand1 strand2):
   strand1.# == strand2.# ||:
     die: 'strands must be of equal length'
-
-  len: map(ne strand1 strand2).filter(a)
+  sum: map(ne strand1 strand2).map(N)
diff --git a/exercises/practice/isogram/.meta/isogram.ys b/exercises/practice/isogram/.meta/isogram.ys
index a352636..0fd4dcb 100644
--- a/exercises/practice/isogram/.meta/isogram.ys
+++ b/exercises/practice/isogram/.meta/isogram.ys
@@ -1,7 +1,4 @@
 !yamlscript/v0
 
-defn isogram(string):
-  empty?(string) ||:
-    lc(string):split      \"Want to be case insensitive"
-      .filter(/^[a-z]$/)  \"Keep letters only"
-      .distinct?(*)       \"Check if distinct letters"
+defn isogram(phrase):
+  phrase !~ /(?i)(\w).*\1/
diff --git a/exercises/practice/list-ops/.meta/list-ops.ys b/exercises/practice/list-ops/.meta/list-ops.ys
index 0c07974..c62c14e 100644
--- a/exercises/practice/list-ops/.meta/list-ops.ys
+++ b/exercises/practice/list-ops/.meta/list-ops.ys
@@ -19,10 +19,4 @@ defn foldl(list initial function):
   list.reduce(function initial)
 
 defn foldr(list initial function):
-  if len(list) > 0:
-    function _ list:first:
-      foldr: rest(list) initial function
-    else: initial
-
-defn reverse(list):
-  core/reverse: list
+  list:reverse.reduce(function initial)
diff --git a/exercises/practice/luhn/.meta/luhn.ys b/exercises/practice/luhn/.meta/luhn.ys
index c3b9698..2698f93 100644
--- a/exercises/practice/luhn/.meta/luhn.ys
+++ b/exercises/practice/luhn/.meta/luhn.ys
@@ -1,18 +1,6 @@
 !yamlscript/v0
 
 defn valid(value):
-  digits =: value.replace(' ')
-
-  and:
-    digits.# >=: 2
-    digits !~: /[^\d]/
-    digits:split:
-      .map(to-num):reverse:V
-      .conj(0).partition(2)
-      .map(munge):flat:sum
-      .mod(10).eq(0)
-
-defn munge([a b]):
-  b *=: 2
-  vector a:
-    if b > 9: (b - 9) b
+  digits =: value.replace(' ').map(\(_ - \\0)):reverse
+  digits.#.gt(1) &&: digits.every?(\(0 <= _ <= 9)) &&
+    map(int.comp(mul) digits [1 2.2]:cycle):sum.mod(10).!
diff --git a/exercises/practice/matching-brackets/.meta/matching-brackets.ys b/exercises/practice/matching-brackets/.meta/matching-brackets.ys
index 64cb419..35f0b8a 100644
--- a/exercises/practice/matching-brackets/.meta/matching-brackets.ys
+++ b/exercises/practice/matching-brackets/.meta/matching-brackets.ys
@@ -1,17 +1,8 @@
 !yamlscript/v0
 
-pairs =: reverse('()[]{}'):M
-opening =: vals(pairs):set
-closing =: keys(pairs):set
-
 defn is-paired(value):
-  loop stack [], [char *chars] value:
-    cond:
-      char:nil?: stack:count:zero?
-      opening(char):
-        recur: conj(stack char) chars
-      closing(char):
-        if peek(stack) == pairs(char):
-          recur: pop(stack) chars
-          else: false
-      else: recur(stack chars)
+  x =: value.replace(/\[\]|\(\)|\{\}|[^(){}\[\]]/)
+  cond:
+    x == '': true
+    x == value: false
+    else: is-paired(x)
diff --git a/exercises/practice/nth-prime/.meta/nth-prime.ys b/exercises/practice/nth-prime/.meta/nth-prime.ys
index aad608f..f578b80 100644
--- a/exercises/practice/nth-prime/.meta/nth-prime.ys
+++ b/exercises/practice/nth-prime/.meta/nth-prime.ys
@@ -1,15 +1,9 @@
 !yamlscript/v0
 
 defn prime(number):
-  lazy-primes().nth(number.--)
-
-defn- lazy-primes(d=2 table={}):
-  if-let factors table.$d:
-    recur d.++:
-      reduce _ table.dissoc(d) factors:
-        \(update-in(%1 [(%2 + d)] conj %2))
-
-    lazy-seq:
-      cons d:
-        lazy-primes d.++:
-          assoc table: sqr(d) [d]
+  loop n 2, u 0:
+    cond:
+      u == number: n.--
+      range(2 sqrt(n):I.++).every?(\((n % _).?)):
+        recur(n.++ u.++)
+      else: recur(n.++ u)
diff --git a/exercises/practice/nucleotide-count/.meta/nucleotide-count.ys b/exercises/practice/nucleotide-count/.meta/nucleotide-count.ys
index 187bad2..7c91796 100644
--- a/exercises/practice/nucleotide-count/.meta/nucleotide-count.ys
+++ b/exercises/practice/nucleotide-count/.meta/nucleotide-count.ys
@@ -1,10 +1,8 @@
 !yamlscript/v0
 
-nucleotides =: zipmap(qw(A C G T) repeat(0))
-
 defn nucleotide-counts(strand):
-  when strand !~ /^[ACGT]*$/:
+  when strand =~ /[^ACGT]/:
     die: 'Invalid nucleotide in strand'
 
-  reduce-kv _ nucleotides frequencies(strand):
-    fn(map key val): map.assoc(str(key) val)
+  into zipmap(qw(A C G T) repeat(0)):
+    frequencies(strand.map(str))
diff --git a/exercises/practice/pangram/.meta/pangram.ys b/exercises/practice/pangram/.meta/pangram.ys
index 081dafe..fe04ae4 100644
--- a/exercises/practice/pangram/.meta/pangram.ys
+++ b/exercises/practice/pangram/.meta/pangram.ys
@@ -1,6 +1,4 @@
 !yamlscript/v0
 
 defn is-pangram(sentence):
-  26 ==: lc(sentence)
-           .replace(/[^a-z]/)
-           .distinct():len
+  B: sentence =~ /(?i)(?>.*?(\pL)(?!.*\1)){26}/
diff --git a/exercises/practice/pascals-triangle/.meta/pascals-triangle.ys b/exercises/practice/pascals-triangle/.meta/pascals-triangle.ys
index 830e110..5f2b15d 100644
--- a/exercises/practice/pascals-triangle/.meta/pascals-triangle.ys
+++ b/exercises/practice/pascals-triangle/.meta/pascals-triangle.ys
@@ -1,11 +1,5 @@
 !yamlscript/v0
 
 defn rows(count):
-  reduce _ [] range(1 count.++):
-    fn(tri row):
-      conj tri:
-        or _ [1]:
-          when row > 1:
-            mapv _ (-1 .. row.sub(2)):
-              \(last(tri).get(_):N.or(0) +
-                last(tri).get(_.++):N.or(0))
+  \(mapv + _.cons(0) _.conj(0))
+    .iterate([1]).take(count)
diff --git a/exercises/practice/perfect-numbers/.meta/perfect-numbers.ys b/exercises/practice/perfect-numbers/.meta/perfect-numbers.ys
index 4ee3f5a..f44dac8 100644
--- a/exercises/practice/perfect-numbers/.meta/perfect-numbers.ys
+++ b/exercises/practice/perfect-numbers/.meta/perfect-numbers.ys
@@ -1,14 +1,13 @@
 !yamlscript/v0
 
 defn classify(number):
-  when number <= 0:
+  when number < 1:
     die: 'Classification is only possible for positive integers.'
 
-  sum-of-divisors =:
-    sum:
-      for n range(1 quot(number 2).++) :when (number % n).!: n
+  nums =:
+    for n range(1 quot(number 2).++) :when (number % n).!: n
 
-  case compare(sum-of-divisors, number):
+  case compare(nums:sum number):
     0  :: perfect
     1  :: abundant
     -1 :: deficient
diff --git a/exercises/practice/pig-latin/.meta/pig-latin.ys b/exercises/practice/pig-latin/.meta/pig-latin.ys
index e999835..2e48f05 100644
--- a/exercises/practice/pig-latin/.meta/pig-latin.ys
+++ b/exercises/practice/pig-latin/.meta/pig-latin.ys
@@ -1,17 +1,9 @@
 !yamlscript/v0
 
-rules =::
-  ^(?:[aeiou]|yt|xr).*::
-    \(_ + 'ay')
-  ^(s?qu|thr|sch|[crst]h|[^aeiou])(.*)::
-    \("$(_.2)$(_.1)ay")
-
 defn translate(phrase):
-  join ' ':
-    map _ words(phrase):
-      fn(word):
-        reduce-kv _ nil rules:
-          fn(translated regex function):
-            match =: word =~ qr(regex)
-            translated ||:
-              match && function(match)
+  replace phrase:
+    /(?x)
+      ([^aeioquxy\s]*
+       (?:qu|q|x|y)?)
+      ([aeiouxy]\w*)/
+    "$2$1ay"
diff --git a/exercises/practice/prime-factors/.meta/prime-factors.ys b/exercises/practice/prime-factors/.meta/prime-factors.ys
index 91fb5cc..e64107d 100644
--- a/exercises/practice/prime-factors/.meta/prime-factors.ys
+++ b/exercises/practice/prime-factors/.meta/prime-factors.ys
@@ -4,5 +4,5 @@ defn factors(value):
   or _ []:
     when value >= 2:
       divisor =: range(2 (value / 2).++)
-        .filter(\((value % _) == 0)):first || value
+        .filter(\((value % _).!)).0 || value
       into [divisor]: factors(quot(value divisor))
diff --git a/exercises/practice/protein-translation/.meta/protein-translation.ys b/exercises/practice/protein-translation/.meta/protein-translation.ys
index 1fb58cc..dc75444 100644
--- a/exercises/practice/protein-translation/.meta/protein-translation.ys
+++ b/exercises/practice/protein-translation/.meta/protein-translation.ys
@@ -2,15 +2,14 @@
 
 defn proteins(strand):
   proteins =:
-    strand.str('XX').partition(3)
-          .map(join).map(translate-codon)
+    strand.re-seq(/.{1,3}/).map(translate)
           .take-while(ne('STOP'))
 
   if proteins.has?('INVALID'):
     die: 'Invalid codon'
     else: proteins
 
-defn translate-codon(codon):
+defn translate(codon):
   case codon:
     ('AUG'                  ) :: Methionine
     ('UUU' 'UUC'            ) :: Phenylalanine
diff --git a/exercises/practice/queen-attack/.meta/queen-attack.ys b/exercises/practice/queen-attack/.meta/queen-attack.ys
index 59c3562..42a4d8e 100644
--- a/exercises/practice/queen-attack/.meta/queen-attack.ys
+++ b/exercises/practice/queen-attack/.meta/queen-attack.ys
@@ -1,20 +1,17 @@
 !yamlscript/v0
 
 defn create(queen):
-  r c =: queen.position.map(qw(row column))
-
+  row col =: queen.position.map(qw(row column))
   cond:
-    r < 0 : die('row not positive')
-    r > 7 : die('row not on board')
-    c < 0 : die('column not positive')
-    c > 7 : die('column not on board')
-    else  : 0
+    row < 0 : die('row not positive')
+    row > 7 : die('row not on board')
+    col < 0 : die('column not positive')
+    col > 7 : die('column not on board')
+    else    : 0
 
 defn can-attack(white-queen black-queen):
-  w-r w-c =: white-queen.position.slice(q(row column))
-  b-r b-c =: black-queen.position.slice(q(row column))
-
-  or:
-    w-r ==: b-r
-    w-c ==: b-c
-    abs(w-r - b-r) ==: abs(w-c - b-c)
+  x =: white-queen.position.row -
+       black-queen.position.row
+  y =: white-queen.position.column -
+       black-queen.position.column
+  (x.! || y.!) ||: x:abs == y:abs
diff --git a/exercises/practice/raindrops/.meta/raindrops.ys b/exercises/practice/raindrops/.meta/raindrops.ys
index d4c64a7..87c04c6 100644
--- a/exercises/practice/raindrops/.meta/raindrops.ys
+++ b/exercises/practice/raindrops/.meta/raindrops.ys
@@ -1,9 +1,5 @@
 !yamlscript/v0
 
 defn convert(number):
-  ps =: M(3 'Pling' 5 'Plang' 7 'Plong')
-  words =:
-    mapcat _ [3 5 7]:
-      fn(n): number.rem(n).! &&& ps.$n
-
-  if words.?: str(words*) str(number)
+  f =: fn([a b] (number % a).!.when(b))
+  or?: map(f [3 5 7] qw(Pling Plang Plong)).str(*) number:S
diff --git a/exercises/practice/rna-transcription/.meta/rna-transcription.ys b/exercises/practice/rna-transcription/.meta/rna-transcription.ys
index 7fa7a7e..0945aed 100644
--- a/exercises/practice/rna-transcription/.meta/rna-transcription.ys
+++ b/exercises/practice/rna-transcription/.meta/rna-transcription.ys
@@ -1,7 +1,4 @@
 !yamlscript/v0
 
-dna-to-rna =:
-  map(split ['GCAT' 'CGUA']).zipmap(*)
-
 defn to-rna(dna):
-  split(dna).map(dna-to-rna):join
+  map(zipmap('GCTA' 'CGAU') dna).str(*)
diff --git a/exercises/practice/roman-numerals/.meta/roman-numerals.ys b/exercises/practice/roman-numerals/.meta/roman-numerals.ys
index 2255920..c1fedec 100644
--- a/exercises/practice/roman-numerals/.meta/roman-numerals.ys
+++ b/exercises/practice/roman-numerals/.meta/roman-numerals.ys
@@ -1,24 +1,8 @@
 !yamlscript/v0
 
-rules =::
-  1000: M
-  900:  CM
-  500:  D
-  400:  CD
-  100:  C
-  90:   XC
-  50:   L
-  40:   XL
-  10:   X
-  9:    IX
-  5:    V
-  4:    IV
-  1:    I
-
 defn roman(number):
-  when number > 0:
-    part letter =:
-      first:
-        filter _ rules:
-          le(number).comp(first)
-    str letter: roman(number - part)
+  nums =: qw(I II III IV V VI VII VIII IX).cons('')
+  reduce _ '' number:S:
+    fn(roman digit):
+      roman.map('IVXLC'.zipmap('XLCDM'))
+           .str(*).str(nums.nth(digit - \\0))
diff --git a/exercises/practice/rotational-cipher/.meta/rotational-cipher.ys b/exercises/practice/rotational-cipher/.meta/rotational-cipher.ys
index 8590461..2151e41 100644
--- a/exercises/practice/rotational-cipher/.meta/rotational-cipher.ys
+++ b/exercises/practice/rotational-cipher/.meta/rotational-cipher.ys
@@ -1,12 +1,6 @@
 !yamlscript/v0
 
-UC =: \\A .. \\Z
-LC =: \\a .. \\z
-
 defn rotate(text shift-key):
-  char-map =:
-    \(zipmap(_ drop(shift-key cycle(_))))
-
-  text:
-    .escape(char-map(UC))
-    .escape(char-map(LC))
+  cmap =: \(zipmap(_ drop(shift-key cycle(_))))
+  text.escape(cmap(\\A .. \\Z)):
+      .escape(cmap(\\a .. \\z))
diff --git a/exercises/practice/scrabble-score/.meta/scrabble-score.ys b/exercises/practice/scrabble-score/.meta/scrabble-score.ys
index 7453de7..862d1ba 100644
--- a/exercises/practice/scrabble-score/.meta/scrabble-score.ys
+++ b/exercises/practice/scrabble-score/.meta/scrabble-score.ys
@@ -1,10 +1,6 @@
 !yamlscript/v0
 
-defn score(word):
-  uc(word):split.map(
-    S(1 'AEIOULNRST') + S(2 'DG') + S(3 'BCMP') +
-    S(4 'FHVWY') + S(5 'K') + S(8 'JX') + S(10 'QZ')
-  ):sum
-
-defn S(score chars):
-  zipmap: chars:split repeat(score)
+scores =: "1332142418513113:11114484:"
+defn score(word): !:sum
+  map _ word:lc:
+    \((_ - \\a).nth(scores):N - \\0)
diff --git a/exercises/practice/secret-handshake/.meta/secret-handshake.ys b/exercises/practice/secret-handshake/.meta/secret-handshake.ys
index 0b94ee5..6df88c9 100644
--- a/exercises/practice/secret-handshake/.meta/secret-handshake.ys
+++ b/exercises/practice/secret-handshake/.meta/secret-handshake.ys
@@ -1,13 +1,6 @@
 !yamlscript/v0
 
-cmds =:: [wink, double blink, close your eyes, jump]
-
 defn commands(number):
-  commands =:
-    range(cmds.#)
-      .map(\(number.bit-test(_) && cmds.get(_)))
-      .filter(a)
-
-  if number.bit-test(cmds.#):
-    commands:reverse
-    commands
+  a =: (0 .. 3).filter(bit-test.P(number))
+    .map(['wink' 'double blink' 'close your eyes' 'jump'])
+  if number.bit-test(4): a:reverse a
diff --git a/exercises/practice/sieve/.meta/sieve.ys b/exercises/practice/sieve/.meta/sieve.ys
index 09ab5e4..5f0d25d 100644
--- a/exercises/practice/sieve/.meta/sieve.ys
+++ b/exercises/practice/sieve/.meta/sieve.ys
@@ -1,12 +1,6 @@
 !yamlscript/v0
 
 defn primes(limit):
-  loop idx 2, primes ([nil nil] + (2 ... limit.++)):
-    if idx < sqrt(limit):
-      recur idx.++:
-        if primes.$idx:
-          map-indexed _ primes:
-            fn(a b):
-              when (a < sqr(idx)) || (a % idx).?: b
-          else: primes
-      filter a: primes
+  nums =: range(2 limit.++)
+  remove _ nums: !:set
+    mapcat _ nums: \(range (_ * 2) limit.++ _)
diff --git a/exercises/practice/space-age/.meta/space-age.ys b/exercises/practice/space-age/.meta/space-age.ys
index 645bacb..7871ba8 100644
--- a/exercises/practice/space-age/.meta/space-age.ys
+++ b/exercises/practice/space-age/.meta/space-age.ys
@@ -1,20 +1,16 @@
 !yamlscript/v0
 
-factors =::
-  Mercury : 0.2408467
-  Venus   : 0.61519726
-  Earth   : 1.0
-  Mars    : 1.8808158
-  Jupiter : 11.862615
-  Saturn  : 29.447498
-  Uranus  : 84.016846
-  Neptune : 164.79132
-
-seconds-in-year =: 365.25 * 24 * 60 * 60
+s =: 365.25 * 24 * 60 * 60
+planets =::
+  Mercury :: s * 0.2408467
+  Venus   :: s * 0.61519726
+  Earth   :: s * 1.0
+  Mars    :: s * 1.8808158
+  Jupiter :: s * 11.862615
+  Saturn  :: s * 29.447498
+  Uranus  :: s * 84.016846
+  Neptune :: s * 164.79132
 
 defn age(planet seconds):
-  factor =: factors.$planet ||
-    die('not a planet')
-
-  seconds / seconds-in-year / factor:
+  seconds.div(planets.$planet.or(die('not a planet')))
     .format('%.2f'):F
diff --git a/exercises/practice/strain/.meta/strain.ys b/exercises/practice/strain/.meta/strain.ys
index ce5a740..a7d4bea 100644
--- a/exercises/practice/strain/.meta/strain.ys
+++ b/exercises/practice/strain/.meta/strain.ys
@@ -1,7 +1,7 @@
 !yamlscript/v0
 
 defn keep(list predicate):
-  mapcat \(when(predicate(_) [_])): list
+  list.filter(predicate)
 
 defn discard(list predicate):
-  mapcat \(when-not(predicate(_) [_])): list
+  list.remove(predicate)
diff --git a/exercises/practice/word-count/.meta/word-count.ys b/exercises/practice/word-count/.meta/word-count.ys
index a9c1ae9..f4c4755 100644
--- a/exercises/practice/word-count/.meta/word-count.ys
+++ b/exercises/practice/word-count/.meta/word-count.ys
@@ -1,8 +1,5 @@
 !yamlscript/v0
 
 defn count-words(sentence):
-  frequencies:
-    lc(sentence)
-      .split(/[^a-z0-9']+/)
-      .map(\(_.replace(/(^'|'$)/)))
-      .remove(empty?)
+  frequencies: lc(sentence)
+    .re-seq(/\w(?:[\w']*\w)?/)
diff --git a/exercises/practice/yacht/.meta/yacht.ys b/exercises/practice/yacht/.meta/yacht.ys
index af58a28..53885f7 100644
--- a/exercises/practice/yacht/.meta/yacht.ys
+++ b/exercises/practice/yacht/.meta/yacht.ys
@@ -1,34 +1,19 @@
 !yamlscript/v0
 
 defn score(dice category):
-  category.replace(/\ / '-')
-    .str('do-' _).call(dice).or(0)
-
-defn- do-yacht(dice): eq(dice*) && 50
-
-defn- same-number(n):
-  fn(dice): dice.filter(eq(n)):sum
-
-do-ones   =: same-number(1)
-do-twos   =: same-number(2)
-do-threes =: same-number(3)
-do-fours  =: same-number(4)
-do-fives  =: same-number(5)
-do-sixes  =: same-number(6)
-
-defn- do-full-house(dice):
-  freqs =: frequencies(dice)
-  when freqs.#.eq(2) && freqs:vals.has?(2):
-    sum: dice
-
-defn- do-four-of-a-kind(dice):
-  freqs =: frequencies(dice):V:reverse:M
-  mul 4: freqs.get(4) || freqs.get(5) || 0
-
-defn- do-little-straight(dice):
-  dice:sort == (1 .. 5) &&: 30
-
-defn- do-big-straight(dice):
-  dice:sort == (2 .. 6) &&: 30
-
-defn- do-choice(dice): sum(dice)
+  dice-set =: dice:distinct:sort
+  counts =: dice:frequencies
+  counts2 =: counts:set/map-invert
+  case category:
+    -'yacht': dice-set.#.eq(1).and(50).or(0)
+    -'choice': dice:sum
+    -'little straight': dice-set.eq([1 2 3 4 5]).and(30).or(0)
+    -'big straight': dice-set.eq([2 3 4 5 6]).and(30).or(0)
+    -'four of a kind': counts2(4 counts2(5 0)) * 4
+    -'full house': (counts2.2 && counts2.3).and(dice:sum).or(0)
+    -'ones'  : counts(1 0) * 1
+    -'twos'  : counts(2 0) * 2
+    -'threes': counts(3 0) * 3
+    -'fours' : counts(4 0) * 4
+    -'fives' : counts(5 0) * 5
+    -'sixes' : counts(6 0) * 6