"Mm. Well, first you need to know the - not exactly composition, but it's the closest word I have - composition of the thing. Which is easy with things like ordinary wood or iron or even steel, but hard for things like, say, attunement stones. And then you use - also not a word for this, this feels very inadequate - prototype threads for making the weave itself. The threads can theoretically make literally everything, but in practice they're sometimes highly unpredictable and are always very fiddly, and you can't tell if what you've made works until it's had anywhere from an hour or two to several days to settle.

"Making the weave's template form a specific shape is harder than just a blob of material, but in practice it tends to be easier than some of the more difficult materials, because the difficult materials get very very difficult, and if you just want whatever you're making to be in, say, the shape of a bed, there is nothing stopping you from using a material that is fairly easy to copy with prototype threads."