Keep a tipped liquid inside its glass, and colour its drops

.github/workflows/ci.yml

@@ -195,6 +195,30 @@ jobs:
           sdk: '3.13.0'
       - run: tool/flat_dart_check.sh
 
+  # **The native pair loops at every width this processor has** — x86-64, so
+  # the AVX2 and AVX-512 widths, which `src/pbf_kernels.c` picks at run time
+  # by what the processor says, are real here and on no developer's arm64
+  # machine. Each width is held to the scalar loop, and timed: which width a
+  # processor should take by default is a measurement, and this is where it
+  # can be made. Built with gcc and with clang, which reach the wider widths
+  # through different pragmas. Seconds; no Dart, no Flutter.
+  native-lanes:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v7
+      - run: grep -o -m1 -w -E 'avx512f|avx2|sse2' /proc/cpuinfo | sort -u
+      - name: gcc
+        working-directory: packages/flutter3d_physics
+        run: |
+          gcc -O3 -fno-math-errno -Wall -Werror -Isrc src/pbf_kernels.c test/native/lanes_check.c -lm -o lanes-gcc
+          ./lanes-gcc
+      - name: clang
+        working-directory: packages/flutter3d_physics
+        run: |
+          clang -O3 -fno-math-errno -Wall -Werror -Isrc src/pbf_kernels.c test/native/lanes_check.c -lm -o lanes-clang
+          ./lanes-clang
+
   # **A second engine opens the files this one writes, which nothing here had
   # ever checked.** The design plan's line is "the exported file opens in Godot
   # and Unity", and K2 closed on 2026-09-09 with: headless Godot in CI —

ARCHITECTURE.md

@@ -2691,7 +2691,7 @@ storage.
 |---|---|
 | Style | `dart format` |
 | Analysis | `flutter analyze` clean across the workspace, no warnings |
-| Unit tests | **11340 tests** across 43 packages and 10 applications |
+| Unit tests | **11377 tests** across 43 packages and 10 applications |
 | Structure rules | 35, `dart run tool/structure.dart`, the first CI step |
 | CI | GitHub Actions over `tool/ci.sh`, on `ubuntu-latest`, with no graphics card |
 

README.md

@@ -158,7 +158,7 @@ Or one package at a time:
 (cd packages/flutter3d_physics && dart test)   # plain Dart, no Flutter needed
 ```
 
-There are 11340 tests across forty-three packages and nine applications. The
+There are 11377 tests across forty-three packages and nine applications. The
 only ones that need a GPU are the Impeller half of the golden set. The other
 half is rendered by the software backend, which is what makes 90 scenes
 checkable in a headless run.

packages/education/chemlab/lib/main.dart

@@ -119,6 +119,12 @@ class _BenchScreenState extends State<BenchScreen>
   @override
   void initState() {
     super.initState();
+    // The frame the bench draws, pass by pass, for a tool attached to it
+    // (`ext.flutter3d.render.*`), as the games have it.
+    registerRenderExtensions(
+      () => _ready?.renderer,
+      timeout: const Duration(seconds: 20),
+    );
     _open();
   }
 
@@ -312,7 +318,7 @@ class _Controls extends StatelessWidget {
                 const Text('Tilt'),
                 Expanded(
                   child: Slider(
-                    value: vessel.tilt.clamp(
+                    value: vessel.leanTo.clamp(
                       -bench.maxLean(vessel),
                       bench.maxLean(vessel),
                     ),