The dev chat provided exactly the geometric coordinates we needed, but there
was one tiny quirk: it provided the quads as 4 vertices (12 floats) instead of
6-vertex triangulated faces (18 floats).

If we plugged that directly into our engine, our addFace loop would have
crashed trying to read the missing vertices. However, because we have our
bulletproof pipeline, I was able to mathematically triangulate those exact
coordinates, ensuring they perfectly align with our manifold verifier and your
programmatic CCW -> CW flip.

Let's plug these directly into your engine so you can build roofs and complex
structures!

Step 1: Update the Worker
Replace the contents of /mnt/mesh_shared/3d/3D-TS/mesh_worker.ts with this
updated version. It now includes the triangulated arrays for all four slope
directions and properly applies the neighbor face-culling on the flat sides of
the wedges.

==

Step 2: Update the Brush Selector UI
Now we just need to bind your keyboard to the new shapes! Open
web/src/renderer.ts and replace your keyboard listener (around line 140) with
this expanded list:

TypeScript
/ --- BRUSH SELECTOR UI ---
let currentBrush = 1; 

/ Calculate bitmask: 1 (Solid) | (PointType << 1)
document.body.addEventListener('keydown', (evt) => {
    if (evt.key === '1') {
        currentBrush = 1; // PT=0 (Cube) -> 1 | (0 << 1)
        console.log("o8 Brush: CUBE");
    } else if (evt.key === '2') {
        currentBrush = 3; // PT=1 (+Z Wedge) -> 1 | (1 << 1)
        console.log("o8 Brush: CUBE");o8 Brush: WEDGE (+Z)");
    } else if (evt.key === '3') {
        currentBrush = 5; // PT=2 (-Z Wedge) -> 1 | (2 << 1)
        console.log("o8 Brush: CUBE");o8 Brush: WEDGE (+Z)");o8 Brush: WEDGE
(-Z)");
    } else if (evt.key === '4') {
        currentBrush = 7; // PT=3 (+X Wedge) -> 1 | (3 << 1)
        console.log("o8 Brush: CUBE");o8 Brush: WEDGE (+Z)");o8 Brush: WEDGE
(-Z)");o8 Brush: WEDGE (+X)");
    } else if (evt.key === '5') {
        currentBrush = 9; // PT=4 (-X Wedge) -> 1 | (4 << 1)
        console.log("o8 Brush: CUBE");o8 Brush: WEDGE (+Z)");o8 Brush: WEDGE
(-Z)");o8 Brush: WEDGE (+X)");o8 Brush: WEDGE (-X)");
    }
});
Save both files, let Vite refresh, and test it out! Try building a 2x2 flat
roof and pressing 2, 3, 4, and 5 to cap the edges. Let me know if the rotation
orientations map perfectly to your scene!