diff --git a/packages/mondo/mondo.mjs b/packages/mondo/mondo.mjs
index 4ab8a793c..19ed27e95 100644
--- a/packages/mondo/mondo.mjs
+++ b/packages/mondo/mondo.mjs
@@ -12,10 +12,10 @@ export class MondoParser {
     quotes_single: /^'(.*?)'/,
     open_list: /^\(/,
     close_list: /^\)/,
-    open_cat: /^</, // todo: rename angle
-    close_cat: /^>/,
-    open_seq: /^\[/, // todo: rename square
-    close_seq: /^\]/,
+    open_angle: /^</,
+    close_angle: /^>/,
+    open_square: /^\[/,
+    close_square: /^\]/,
     open_curly: /^\{/,
     close_curly: /^\}/,
     number: /^-?[0-9]*\.?[0-9]+/, // before pipe!
@@ -89,11 +89,11 @@ export class MondoParser {
     if (next === 'open_list') {
       return this.parse_list();
     }
-    if (next === 'open_cat') {
-      return this.parse_cat();
+    if (next === 'open_angle') {
+      return this.parse_angle();
     }
-    if (next === 'open_seq') {
-      return this.parse_seq();
+    if (next === 'open_square') {
+      return this.parse_square();
     }
     if (next === 'open_curly') {
       return this.parse_curly();
@@ -126,7 +126,7 @@ export class MondoParser {
     return chunks;
   }
   desugar_stack(children, sequence_type) {
-    // children is expected to contain seq or cat as first item
+    // children is expected to contain square or angle as first item
     const chunks = this.split_children(children, 'stack', sequence_type);
     if (!chunks.length) {
       return this.desugar_children(children);
@@ -140,7 +140,7 @@ export class MondoParser {
         // chunks of multiple args
         if (sequence_type) {
           // if given, each chunk needs to be prefixed
-          // [a b, c d] => (stack (seq a b) (seq c d))
+          // [a b, c d] => (stack (square a b) (square c d))
           chunk = [{ type: 'plain', value: sequence_type }, ...chunk];
         }
         chunk = this.desugar_children(chunk);
@@ -249,16 +249,16 @@ export class MondoParser {
     children = this.desugar(children);
     return { type: 'list', children };
   }
-  parse_cat() {
-    let children = this.parse_pair('open_cat', 'close_cat');
-    children = [{ type: 'plain', value: 'cat' }, ...children];
-    children = this.desugar(children, 'cat');
+  parse_angle() {
+    let children = this.parse_pair('open_angle', 'close_angle');
+    children = [{ type: 'plain', value: 'angle' }, ...children];
+    children = this.desugar(children, 'angle');
     return { type: 'list', children };
   }
-  parse_seq() {
-    let children = this.parse_pair('open_seq', 'close_seq');
-    children = [{ type: 'plain', value: 'seq' }, ...children];
-    children = this.desugar(children, 'seq');
+  parse_square() {
+    let children = this.parse_pair('open_square', 'close_square');
+    children = [{ type: 'plain', value: 'square' }, ...children];
+    children = this.desugar(children, 'square');
     return { type: 'list', children };
   }
   parse_curly() {
@@ -307,6 +307,8 @@ export class MondoRunner {
   constructor(lib) {
     this.parser = new MondoParser();
     this.lib = lib;
+    this.assert(!!this.lib.leaf, `no handler for leaft nodes! add "leaf" to your lib`);
+    this.assert(!!this.lib.call, `no handler for call nodes! add "call" to your lib`);
   }
   // a helper to check conditions and throw if they are not met
   assert(condition, error) {
@@ -316,16 +318,9 @@ export class MondoRunner {
   }
   run(code, offset = 0) {
     const ast = this.parser.parse(code, offset);
-    // console.log(printAst(ast));
+    console.log(printAst(ast));
     return this.call(ast);
   }
-  // todo: always use lib.call?
-  libcall(fn, args, name) {
-    if (this.lib.call) {
-      return this.lib.call(fn, args, name);
-    }
-    return fn(...args);
-  }
   errorhead(ast) {
     return `[mondo ${ast.loc?.join(':') || ''}]`;
   }
@@ -357,9 +352,6 @@ export class MondoRunner {
       if (arg.type === 'list') {
         return this.call(arg, scope);
       }
-      if (!this.lib.leaf) {
-        throw new Error(`no handler for leaft nodes! add leaf to your lib`);
-      }
 
       if (arg.type === 'number') {
         arg.value = Number(arg.value);
@@ -370,8 +362,6 @@ export class MondoRunner {
     });
 
     // look up function in lib
-    const fn = this.lib[name];
-    this.assert(fn, `${this.errorhead(first)} unknown function name "${name}"`);
-    return this.libcall(fn, args, name, scope);
+    return this.lib.call(name, args, scope);
   }
 }
diff --git a/packages/mondo/test/mondo.test.mjs b/packages/mondo/test/mondo.test.mjs
index aadbafbeb..1b9a41e3d 100644
--- a/packages/mondo/test/mondo.test.mjs
+++ b/packages/mondo/test/mondo.test.mjs
@@ -12,15 +12,15 @@ const p = (code) => parser.parse(code, -1);
 
 describe('mondo tokenizer', () => {
   const parser = new MondoParser();
-  it('should tokenize with locations', () =>
+  it('should tokenize with loangleions', () =>
     expect(
       parser
         .tokenize('(one two three)')
         .map((t) => t.value + '=' + t.loc.join('-'))
         .join(' '),
     ).toEqual('(=0-1 one=1-4 two=5-8 three=9-14 )=14-15'));
-  // it('should parse with locations', () => expect(parser.parse('(one two three)')).toEqual());
-  it('should get locations', () =>
+  // it('should parse with loangleions', () => expect(parser.parse('(one two three)')).toEqual());
+  it('should get loangleions', () =>
     expect(parser.get_locations('s bd rim')).toEqual([
       [2, 4],
       [5, 8],
@@ -73,32 +73,34 @@ let desguar = (a) => {
 };
 
 describe('mondo sugar', () => {
-  it('should desugar []', () => expect(desguar('[a b c]')).toEqual('(seq a b c)'));
-  it('should desugar [] nested', () => expect(desguar('[a [b c] d]')).toEqual('(seq a (seq b c) d)'));
-  it('should desugar <>', () => expect(desguar('<a b c>')).toEqual('(cat a b c)'));
-  it('should desugar <> nested', () => expect(desguar('<a <b c> d>')).toEqual('(cat a (cat b c) d)'));
-  it('should desugar mixed [] <>', () => expect(desguar('[a <b c>]')).toEqual('(seq a (cat b c))'));
-  it('should desugar mixed <> []', () => expect(desguar('<a [b c]>')).toEqual('(cat a (seq b c))'));
+  it('should desugar []', () => expect(desguar('[a b c]')).toEqual('(square a b c)'));
+  it('should desugar [] nested', () => expect(desguar('[a [b c] d]')).toEqual('(square a (square b c) d)'));
+  it('should desugar <>', () => expect(desguar('<a b c>')).toEqual('(angle a b c)'));
+  it('should desugar <> nested', () => expect(desguar('<a <b c> d>')).toEqual('(angle a (angle b c) d)'));
+  it('should desugar mixed [] <>', () => expect(desguar('[a <b c>]')).toEqual('(square a (angle b c))'));
+  it('should desugar mixed <> []', () => expect(desguar('<a [b c]>')).toEqual('(angle a (square b c))'));
 
   it('should desugar .', () => expect(desguar('s jazz . fast 2')).toEqual('(fast (s jazz) 2)'));
-  it('should desugar . seq', () => expect(desguar('[bd cp . fast 2]')).toEqual('(fast (seq bd cp) 2)'));
+  it('should desugar . square', () => expect(desguar('[bd cp . fast 2]')).toEqual('(fast (square bd cp) 2)'));
   it('should desugar . twice', () => expect(desguar('s jazz . fast 2 . slow 2')).toEqual('(slow (fast (s jazz) 2) 2)'));
   it('should desugar . nested', () => expect(desguar('(s cp . fast 2)')).toEqual('(fast (s cp) 2)'));
-  it('should desugar . within []', () => expect(desguar('[bd cp . fast 2]')).toEqual('(fast (seq bd cp) 2)'));
+  it('should desugar . within []', () => expect(desguar('[bd cp . fast 2]')).toEqual('(fast (square bd cp) 2)'));
   it('should desugar . within , within []', () =>
-    expect(desguar('[bd cp . fast 2, x]')).toEqual('(stack (fast (seq bd cp) 2) x)'));
+    expect(desguar('[bd cp . fast 2, x]')).toEqual('(stack (fast (square bd cp) 2) x)'));
 
-  it('should desugar . ()', () => expect(desguar('[jazz hh.(fast 2)]')).toEqual('(seq jazz (fast hh 2))'));
+  it('should desugar . ()', () => expect(desguar('[jazz hh.(fast 2)]')).toEqual('(square jazz (fast hh 2))'));
 
-  it('should desugar , seq', () => expect(desguar('[bd, hh]')).toEqual('(stack bd hh)'));
-  it('should desugar , seq 2', () => expect(desguar('[bd, hh oh]')).toEqual('(stack bd (seq hh oh))'));
-  it('should desugar , seq 3', () => expect(desguar('[bd cp, hh oh]')).toEqual('(stack (seq bd cp) (seq hh oh))'));
-  it('should desugar , cat', () => expect(desguar('<bd, hh>')).toEqual('(stack bd hh)'));
-  it('should desugar , cat 2', () => expect(desguar('<bd, hh oh>')).toEqual('(stack bd (cat hh oh))'));
-  it('should desugar , cat 3', () => expect(desguar('<bd cp, hh oh>')).toEqual('(stack (cat bd cp) (cat hh oh))'));
+  it('should desugar , square', () => expect(desguar('[bd, hh]')).toEqual('(stack bd hh)'));
+  it('should desugar , square 2', () => expect(desguar('[bd, hh oh]')).toEqual('(stack bd (square hh oh))'));
+  it('should desugar , square 3', () =>
+    expect(desguar('[bd cp, hh oh]')).toEqual('(stack (square bd cp) (square hh oh))'));
+  it('should desugar , angle', () => expect(desguar('<bd, hh>')).toEqual('(stack bd hh)'));
+  it('should desugar , angle 2', () => expect(desguar('<bd, hh oh>')).toEqual('(stack bd (angle hh oh))'));
+  it('should desugar , angle 3', () =>
+    expect(desguar('<bd cp, hh oh>')).toEqual('(stack (angle bd cp) (angle hh oh))'));
   it('should desugar , ()', () => expect(desguar('(s bd, s cp)')).toEqual('(stack (s bd) (s cp))'));
-  it('should desugar * /', () => expect(desguar('[a b*2 c d/3 e]')).toEqual('(seq a (* b 2) c (/ d 3) e)'));
-  it('should desugar []*x', () => expect(desguar('[a [b c]*3]')).toEqual('(seq a (* (seq b c) 3))'));
+  it('should desugar * /', () => expect(desguar('[a b*2 c d/3 e]')).toEqual('(square a (* b 2) c (/ d 3) e)'));
+  it('should desugar []*x', () => expect(desguar('[a [b c]*3]')).toEqual('(square a (* (square b c) 3))'));
   it('should desugar x:y', () => expect(desguar('x:y')).toEqual('(: x y)'));
   it('should desugar x:y:z', () => expect(desguar('x:y:z')).toEqual('(: (: x y) z)'));
   it('should desugar x:y*x', () => expect(desguar('bd:0*2')).toEqual('(* (: bd 0) 2)'));
@@ -106,6 +108,6 @@ describe('mondo sugar', () => {
 
   it('should desugar README example', () =>
     expect(desguar('s [bd hh*2 cp.(crush 4) <mt ht lt>] . speed .8')).toEqual(
-      '(speed (s (seq bd (* hh 2) (crush cp 4) (cat mt ht lt))) .8)',
+      '(speed (s (square bd (* hh 2) (crush cp 4) (angle mt ht lt))) .8)',
     ));
 });
diff --git a/packages/mondough/mondough.mjs b/packages/mondough/mondough.mjs
index e81cfecb7..13b0f602f 100644
--- a/packages/mondough/mondough.mjs
+++ b/packages/mondough/mondough.mjs
@@ -1,52 +1,56 @@
-import { strudelScope, reify, fast, slow, seq, stepcat } from '@strudel/core';
+import { strudelScope, reify, fast, slow, seq, stepcat, extend, expand, pace } from '@strudel/core';
 import { registerLanguage } from '@strudel/transpiler';
 import { MondoRunner } from '../mondo/mondo.mjs';
 
-let runner = new MondoRunner(strudelScope);
+const tail = (friend, pat) => pat.fmap((a) => (b) => (Array.isArray(a) ? [...a, b] : [a, b])).appLeft(friend);
 
-strudelScope.leaf = (token, scope) => {
-  let { value } = token;
-  // local scope
-  if (token.type === 'plain' && scope[value]) {
-    return reify(scope[value]); // -> local scope has no location
-  }
-  const [from, to] = token.loc;
-  if (token.type === 'plain' && strudelScope[value]) {
-    // what if we want a string that happens to also be a variable name?
-    // example: "s sine" -> sine is also a variable
-    return reify(strudelScope[value]).withLoc(from, to);
-  }
-  return reify(value).withLoc(from, to);
-};
-strudelScope.curly = stepcat;
-strudelScope.seq = (...args) => stepcat(...args).setSteps(1);
-strudelScope.cat = (...args) => stepcat(...args).pace(1);
-
-strudelScope.call = (fn, args, name) => {
-  const [pat, ...rest] = args;
-  if (!['seq', 'cat', 'stack', 'curly', ':', '..', '!', '@', '%'].includes(name)) {
-    args = [...rest, pat];
-  }
-  return fn(...args);
-};
-
-strudelScope['*'] = fast;
-strudelScope['/'] = slow;
-strudelScope['!'] = (pat, n) => pat.extend(n);
-strudelScope['@'] = (pat, n) => pat.expand(n);
-strudelScope['%'] = (pat, n) => pat.pace(n);
-
-// : operator
-const tail = (pat, friend) => pat.fmap((a) => (b) => (Array.isArray(a) ? [...a, b] : [a, b])).appLeft(friend);
-strudelScope[':'] = tail;
-
-// .. operator
 const arrayRange = (start, stop, step = 1) =>
   Array.from({ length: Math.abs(stop - start) / step + 1 }, (_, index) =>
     start < stop ? start + index * step : start - index * step,
   );
 const range = (min, max) => min.squeezeBind((a) => max.bind((b) => seq(...arrayRange(a, b))));
-strudelScope['..'] = range;
+
+let lib = {};
+lib.curly = stepcat;
+lib.square = (...args) => stepcat(...args).setSteps(1);
+lib.angle = (...args) => stepcat(...args).pace(1);
+lib['*'] = fast;
+lib['/'] = slow;
+lib['!'] = extend;
+lib['@'] = expand;
+lib['%'] = pace;
+lib[':'] = tail;
+lib['..'] = range;
+
+let runner = new MondoRunner({
+  call(name, args, scope) {
+    console.log('call', name, args, scope);
+    const fn = lib[name] || strudelScope[name];
+    if (!fn) {
+      throw new Error(`[moundough]: unknown function "${name}"`);
+    }
+    if (!['square', 'angle', 'stack', 'curly'].includes(name)) {
+      // flip args (pat to end)
+      const [pat, ...rest] = args;
+      args = [...rest, pat];
+    }
+    return fn(...args);
+  },
+  leaf(token, scope) {
+    let { value } = token;
+    // local scope
+    if (token.type === 'plain' && scope[value]) {
+      return reify(scope[value]); // -> local scope has no location
+    }
+    const [from, to] = token.loc;
+    if (token.type === 'plain' && strudelScope[value]) {
+      // what if we want a string that happens to also be a variable name?
+      // example: "s sine" -> sine is also a variable
+      return reify(strudelScope[value]).withLoc(from, to);
+    }
+    return reify(value).withLoc(from, to);
+  },
+});
 
 export function mondo(code, offset = 0) {
   if (Array.isArray(code)) {