Fix: update docs about snd

docs/tutorials/harmony.md

@@ -7,17 +7,17 @@ This tutorial covers everything pitch-related: notes, intervals, chords, voicing
 A note name followed by an octave number compiles to a MIDI integer:
 
 ```forth
-c4 note sine s .
+c4 note sine snd .
 ```
 
 That plays middle C (MIDI 60). `a4` is concert A (69), `e3` is 52. Sharps use `s` or `#`, flats use `b`:
 
 ```forth
-fs4 note 0.5 decay saw s .
+fs4 note 0.5 decay saw snd .
 ```
 
 ```forth
-eb4 note 0.8 decay tri s .
+eb4 note 0.8 decay tri snd .
 ```
 
 `fs4` and `f#4` both mean F sharp 4 (MIDI 66). `bb3` is B flat 3 (58). Octave range is -1 to 9.
@@ -29,13 +29,13 @@ Notes are just integers. They work anywhere an integer works — you can do arit
 An interval duplicates the top of the stack and adds semitones. Stack two intervals to build a chord by hand:
 
 ```forth
-c4 M3 P5 note 1.5 decay sine s .
+c4 M3 P5 note 1.5 decay sine snd .
 ```
 
 That builds a C major triad from scratch: C4 (60), then a major third above (64), then a perfect fifth above the root (67). Three notes on the stack, all played together.
 
 ```forth
-a3 m3 P5 note 1.2 decay va s .
+a3 m3 P5 note 1.2 decay va snd .
 ```
 
 A minor triad: A3, C4, E4.
@@ -78,7 +78,7 @@ A minor triad: A3, C4, E4.
 Custom voicings with wide intervals:
 
 ```forth
-c3 P5 P8 M10 note 1.5 decay sine s .
+c3 P5 P8 M10 note 1.5 decay sine snd .
 ```
 
 C3, G3, C4, E4 — an open-voiced C major spread across two octaves.
@@ -88,21 +88,21 @@ C3, G3, C4, E4 — an open-voiced C major spread across two octaves.
 Chord words replace a root note with all the chord tones. They're shortcuts for what intervals do manually:
 
 ```forth
-c4 maj note 1.5 decay sine s .
+c4 maj note 1.5 decay sine snd .
 ```
 
 That's the same C major triad, but in one word instead of `M3 P5`. A few more:
 
 ```forth
-d3 min7 note 1.5 decay va s .
+d3 min7 note 1.5 decay va snd .
 ```
 
 ```forth
-e3 dom9 note 1.2 decay saw s .
+e3 dom9 note 1.2 decay saw snd .
 ```
 
 ```forth
-a3 sus2 note 1.5 decay tri s .
+a3 sus2 note 1.5 decay tri snd .
 ```
 
 Common triads:
@@ -140,19 +140,19 @@ Four words reshape chord voicings without changing the harmony.
 `inv` moves the bottom note up an octave (inversion):
 
 ```forth
-c4 maj inv note 1.5 decay sine s .
+c4 maj inv note 1.5 decay sine snd .
 ```
 
 The root C goes up, giving E4 G4 C5 — first inversion. Apply it twice for second inversion:
 
 ```forth
-c4 maj inv inv note 1.5 decay sine s .
+c4 maj inv inv note 1.5 decay sine snd .
 ```
 
 G4 C5 E5. `dinv` does the opposite — moves the top note down an octave:
 
 ```forth
-c4 maj dinv note 1.5 decay sine s .
+c4 maj dinv note 1.5 decay sine snd .
 ```
 
 G3 C4 E4. The fifth drops below the root.
@@ -160,13 +160,13 @@ G3 C4 E4. The fifth drops below the root.
 `drop2` and `drop3` are jazz voicing techniques for four-note chords. `drop2` takes the second-from-top note and drops it an octave:
 
 ```forth
-c4 maj7 drop2 note 1.2 decay va s .
+c4 maj7 drop2 note 1.2 decay va snd .
 ```
 
 From C4 E4 G4 B4, the G drops to G3: G3 C4 E4 B4. `drop3` drops the third-from-top:
 
 ```forth
-c4 maj7 drop3 note 1.2 decay va s .
+c4 maj7 drop3 note 1.2 decay va snd .
 ```
 
 E drops to E3: E3 C4 G4 B4. These create wider, more open voicings common in jazz guitar and piano.
@@ -176,13 +176,13 @@ E drops to E3: E3 C4 G4 B4. These create wider, more open voicings common in jaz
 `tp` shifts every note on the stack by N semitones:
 
 ```forth
-c4 maj 3 tp note 1.5 decay sine s .
+c4 maj 3 tp note 1.5 decay sine snd .
 ```
 
 C major transposed up 3 semitones becomes Eb major. Works with any number of notes:
 
 ```forth
-c4 min7 -2 tp note 1.5 decay va s .
+c4 min7 -2 tp note 1.5 decay va snd .
 ```
 
 Shifts the whole chord down 2 semitones (Bb minor 7).
@@ -190,14 +190,14 @@ Shifts the whole chord down 2 semitones (Bb minor 7).
 `oct` shifts a single note by octaves:
 
 ```forth
-c4 1 oct note 0.3 decay sine s .
+c4 1 oct note 0.3 decay sine snd .
 ```
 
 C5 (one octave up). Useful for bass lines:
 
 ```forth
 0 2 4 5 7 5 4 2 8 cycle minor note
--2 oct 0.8 gain sine s .
+-2 oct 0.8 gain sine snd .
 ```
 
 ## Scales
@@ -205,7 +205,7 @@ C5 (one octave up). Useful for bass lines:
 Scale words convert a degree index into a MIDI note. By default the root is C4 (MIDI 60):
 
 ```forth
-0 major note 0.5 decay sine s .
+0 major note 0.5 decay sine snd .
 ```
 
 Degree 0 of the major scale: C4. Degrees wrap with octave transposition — degree 7 gives C5 (72), degree -1 gives B3 (59).
@@ -213,13 +213,13 @@ Degree 0 of the major scale: C4. Degrees wrap with octave transposition — degr
 Walk through a scale with `cycle`:
 
 ```forth
-0 1 2 3 4 5 6 7 8 cycle minor note 0.5 decay sine s .
+0 1 2 3 4 5 6 7 8 cycle minor note 0.5 decay sine snd .
 ```
 
 Random notes from a scale:
 
 ```forth
-0 7 rand pentatonic note 0.8 decay va s .
+0 7 rand pentatonic note 0.8 decay va snd .
 ```
 
 ### Setting the key
@@ -227,13 +227,13 @@ Random notes from a scale:
 By default scales are rooted at C4. Use `key!` to change the tonal center:
 
 ```forth
-g3 key! 0 major note 0.5 decay sine s .
+g3 key! 0 major note 0.5 decay sine snd .
 ```
 
 Now degree 0 is G3 (55) instead of C4. The key persists across steps until changed again:
 
 ```forth
-a3 key! 0 3 5 7 3 cycle minor note 0.8 decay tri s .
+a3 key! 0 3 5 7 3 cycle minor note 0.8 decay tri snd .
 ```
 
 A minor melody starting from A3.
@@ -261,19 +261,19 @@ Jazz, symmetric, and modal variant scales are listed in the Reference section.
 `triad` and `seventh` build chords from scale degrees. Instead of specifying a chord type, you get whatever chord the scale produces at that degree:
 
 ```forth
-0 major triad note 1.5 decay sine s .
+0 major triad note 1.5 decay sine snd .
 ```
 
 Degree 0 of the major scale, stacked in thirds: C E G — a major triad. The scale determines the chord quality automatically. Degree 1 gives D F A (minor), degree 4 gives G B D (major):
 
 ```forth
-4 major triad note 1.5 decay sine s .
+4 major triad note 1.5 decay sine snd .
 ```
 
 `seventh` adds a fourth note:
 
 ```forth
-0 major seventh note 1.2 decay va s .
+0 major seventh note 1.2 decay va snd .
 ```
 
 C E G B — Cmaj7. Degree 1 gives Dm7, degree 4 gives G7 (dominant). The diatonic context determines everything.
@@ -281,7 +281,7 @@ C E G B — Cmaj7. Degree 1 gives Dm7, degree 4 gives G7 (dominant). The diatoni
 Combine with `key!` to play diatonic chords in any key:
 
 ```forth
-g3 key! 0 major triad note 1.5 decay sine s .
+g3 key! 0 major triad note 1.5 decay sine snd .
 ```
 
 G major triad rooted at G3.
@@ -291,7 +291,7 @@ A I-vi-IV-V chord progression using `pcycle`:
 ```forth
 ( 0 major seventh ) ( 5 major seventh )
 ( 3 major seventh ) ( 4 major seventh ) 4 pcycle
-note 1.2 decay va s .
+note 1.2 decay va snd .
 ```
 
 Combine with voicings for smoother voice leading:
@@ -299,13 +299,13 @@ Combine with voicings for smoother voice leading:
 ```forth
 ( 0 major seventh ) ( 5 major seventh inv )
 ( 3 major seventh ) ( 4 major seventh drop2 ) 4 pcycle
-note 1.5 decay va s .
+note 1.5 decay va snd .
 ```
 
 Arpeggiate diatonic chords using `arp` (see the *Timing with at* tutorial for details on `arp`):
 
 ```forth
-0 major seventh arp note 0.5 decay sine s .
+0 major seventh arp note 0.5 decay sine snd .
 ```
 
 ## Frequency Conversion
@@ -313,7 +313,7 @@ Arpeggiate diatonic chords using `arp` (see the *Timing with at* tutorial for de
 `mtof` converts a MIDI note to frequency in Hz. `ftom` does the reverse:
 
 ```forth
-c4 mtof freq sine s .
+c4 mtof freq sine snd .
 ```
 
 Useful when a synth parameter expects Hz rather than MIDI.