Fix: update docs about snd

docs/tutorials/at.md

@@ -7,19 +7,19 @@ Every step has a duration. By default, sounds emit at the very start of that dur
 `at` drains the entire stack and stores the values as timing offsets. Each value is a fraction of the step duration: 0 = start, 0.5 = halfway, 1.0 = next step boundary.
 
 ```forth
-0.5 at kick s .         ;; kick at the midpoint
+0.5 at kick snd .         ;; kick at the midpoint
 ```
 
 Push multiple values before calling `at` to get multiple emits from a single `.`:
 
 ```forth
-0 0.5 at kick s .
+0 0.5 at kick snd .
 ```
 
 Two kicks: one at start, one at midpoint.
 
 ```forth
-0 0.25 0.5 0.75 at hat s .
+0 0.25 0.5 0.75 at hat snd .
 ```
 
 Four hats, evenly spaced.
@@ -28,10 +28,10 @@ The deltas persist across multiple `.` calls until `clear` or a new `at`:
 
 ```forth
 0 0.5 at
-kick s .                ;; 2 kicks
-hat s .                 ;; 2 hats (same timing)
+kick snd .                ;; 2 kicks
+hat snd .                 ;; 2 hats (same timing)
 clear
-snare s .               ;; 1 snare (deltas cleared)
+snare snd .               ;; 1 snare (deltas cleared)
 ```
 
 ## Cross-product: at Without arp
@@ -40,7 +40,7 @@ Without `arp`, deltas multiply with polyphonic voices. If you have 3 notes and 2
 
 ```forth
 0 0.5 at
-c4 e4 g4 note 1.5 decay sine s .
+c4 e4 g4 note 1.5 decay sine snd .
 ```
 
 6 emits: 3 notes x 2 deltas. A chord played twice per step.
@@ -51,7 +51,7 @@ c4 e4 g4 note 1.5 decay sine s .
 
 ```forth
 0 0.33 0.66 at
-c4 e4 g4 arp note 0.5 decay sine s .
+c4 e4 g4 arp note 0.5 decay sine snd .
 ```
 
 C4 at 0, E4 at 0.33, G4 at 0.66.
@@ -60,7 +60,7 @@ If the lists differ in length, the shorter one wraps around:
 
 ```forth
 0 0.25 0.5 0.75 at
-c4 e4 arp note 0.3 decay sine s .
+c4 e4 arp note 0.3 decay sine snd .
 ```
 
 C4, E4, C4, E4 — the shorter list wraps to fill 4 time points.
@@ -74,25 +74,25 @@ You rarely type deltas by hand. Use generators:
 Evenly spaced via `.,`:
 
 ```forth
-0 1 0.25 ., at hat s .        ;; 0 0.25 0.5 0.75 1.0
+0 1 0.25 ., at hat snd .        ;; 0 0.25 0.5 0.75 1.0
 ```
 
 Euclidean distribution via `euclid`:
 
 ```forth
-3 8 euclid at hat s .         ;; 3 hats at positions 0, 3, 5
+3 8 euclid at hat snd .         ;; 3 hats at positions 0, 3, 5
 ```
 
 Random timing via `gen`:
 
 ```forth
-( 0.0 1.0 rand ) 4 gen at hat s .   ;; 4 hats at random positions
+( 0.0 1.0 rand ) 4 gen at hat snd .   ;; 4 hats at random positions
 ```
 
 Geometric spacing via `geom..`:
 
 ```forth
-0.0 2.0 4 geom.. at hat s .  ;; exponentially spaced
+0.0 2.0 4 geom.. at hat snd .  ;; exponentially spaced
 ```
 
 ## Gating at
@@ -101,14 +101,14 @@ Wrap `at` expressions in quotations for conditional timing:
 
 ```forth
 ( 0 0.25 0.5 0.75 at ) 2 every
-hat s .
+hat snd .
 ```
 
 16th-note hats every other bar.
 
 ```forth
 ( 0 0.5 at ) 0.5 chance
-kick s .
+kick snd .
 ```
 
 50% chance of double-hit.