diff --git a/ACCESSIBILITY.md b/ACCESSIBILITY.md
index 6d3f1d9..f53be85 100644
--- a/ACCESSIBILITY.md
+++ b/ACCESSIBILITY.md
@@ -11,7 +11,7 @@ default.
 
 > **Scope:** every active SceneryStack TypeScript simulation in
 > [`structure/repos.json`](structure/repos.json) (`isSimulation` + `framework: SceneryStack`)
-> plus `SceneryStackTemplate`. As of 2026-08-05 that is 31 sims including ACPhasor,
+> plus `SceneryStackTemplate`. As of 2026-08-12 that is 37 sims including ACPhasor,
 > BasicCoordinatesAndSeasons, CarnotHeatEngine, HabitableZones, LightPropagation, MotionsOfTheSun,
 > Oscilloscope, Precession, SpecialRelativity, SternGerlach, and Zenith. The hardware
 > web UI `tscd48` and the Python apps are out of scope and keep their own a11y docs.
diff --git a/CONVENTIONS.md b/CONVENTIONS.md
index 337a7c1..8540e15 100644
--- a/CONVENTIONS.md
+++ b/CONVENTIONS.md
@@ -12,7 +12,7 @@ conformant by default.
 
 > **Scope:** every active SceneryStack TypeScript simulation in
 > [`structure/repos.json`](structure/repos.json) (`isSimulation` + `framework: SceneryStack`)
-> plus `SceneryStackTemplate`. As of 2026-08-05 that is 31 sims including ACPhasor,
+> plus `SceneryStackTemplate`. As of 2026-08-12 that is 37 sims including ACPhasor,
 > BasicCoordinatesAndSeasons, CarnotHeatEngine, HabitableZones, LightPropagation, MotionsOfTheSun,
 > Oscilloscope, Precession, SpecialRelativity, SternGerlach, and Zenith. The hardware
 > web UI `tscd48` and the Python apps (`pyro`, `pycd48`) are out of scope. Orchestration (`Baton`)
diff --git a/docs/assets/StandingWaves.webp b/docs/assets/StandingWaves.webp
new file mode 100644
index 0000000..2d9183b
Binary files /dev/null and b/docs/assets/StandingWaves.webp differ
diff --git a/docs/index.html b/docs/index.html
index 78a3bba..0e4f7a7 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -283,7 +283,7 @@ <h1>OpenPhysics</h1>
     <section>
       <div class="section-head">
         <h2>Core Simulations</h2>
-        <span class="count">21</span>
+        <span class="count">23</span>
       </div>
       <div class="grid">
         <a class="card" href="https://openphysics.github.io/ACPhasor/" style="--hue: 33;">
@@ -473,6 +473,17 @@ <h3>Special Relativity</h3>
             <div class="tags"><span class="tag">special relativity</span><span class="tag">spacetime</span><span class="tag">time dilation</span></div>
           </div>
         </a>
+        <a class="card" href="https://openphysics.github.io/StandingWaves/" style="--hue: 262;">
+          <div class="thumb"><img src="assets/StandingWaves.webp" alt="Standing Waves simulation screenshot" loading="lazy" decoding="async" width="1154" height="753"><span class="badge">SW</span></div>
+          <div class="card-body">
+            <div class="card-head">
+              <h3>Standing Waves</h3>
+              <span class="card-arrow" aria-hidden="true">&rarr;</span>
+            </div>
+            <p>Longitudinal standing waves in a pipe: displacement, velocity and pressure phase relationships, open vs. closed end reflection, and the harmonic series of open and stopped pipes.</p>
+            <div class="tags"><span class="tag">standing waves</span><span class="tag">acoustics</span><span class="tag">pipes</span></div>
+          </div>
+        </a>
         <a class="card" href="https://openphysics.github.io/SternGerlach/" style="--hue: 138;">
           <div class="thumb"><img src="assets/SternGerlach.webp" alt="Stern–Gerlach simulation screenshot" loading="lazy" decoding="async" width="1154" height="753"><span class="badge">SG</span></div>
           <div class="card-body">
@@ -705,7 +716,7 @@ <h3>Variable Star Photometry</h3>
     </main>
 
     <footer>
-      <p>35 live simulations &middot; Built with <a href="https://scenerystack.org/">SceneryStack</a> &middot; GNU Affero GPL v3 &middot;
+      <p>37 live simulations &middot; Built with <a href="https://scenerystack.org/">SceneryStack</a> &middot; GNU Affero GPL v3 &middot;
       <a href="https://github.com/OpenPhysics/Baton">OpenPhysics/Baton</a></p>
     </footer>
   </div>
diff --git a/screenshots/StandingWaves.png b/screenshots/StandingWaves.png
new file mode 100644
index 0000000..5013775
Binary files /dev/null and b/screenshots/StandingWaves.png differ
diff --git a/structure/repos.json b/structure/repos.json
index 02326fb..4a08f5d 100644
--- a/structure/repos.json
+++ b/structure/repos.json
@@ -969,6 +969,33 @@
       ],
       "status": "active"
     },
+    {
+      "name": "StandingWaves",
+      "displayName": "Standing Waves",
+      "type": "simulation",
+      "isSimulation": true,
+      "lineage": "original",
+      "upstream": null,
+      "language": [
+        "TypeScript"
+      ],
+      "framework": "SceneryStack",
+      "description": "Longitudinal standing waves in a pipe: displacement, velocity and pressure phase relationships, open vs. closed end reflection, and the harmonic series of open and stopped pipes.",
+      "deployedUrl": "https://openphysics.github.io/StandingWaves",
+      "physicsTopics": [
+        "standing waves",
+        "acoustics",
+        "pipes",
+        "harmonics"
+      ],
+      "screens": [
+        "Reflection",
+        "Phase",
+        "Standing Waves",
+        "Instruments"
+      ],
+      "status": "active"
+    },
     {
       "name": "SternGerlach",
       "displayName": "Stern\u2013Gerlach",