Method subtract

docs/app/js/sanddance-app.js:69327–69330

(...vectors)

        return this.check();
    }
    subtract(...vectors) {
        for (const vector of vectors)for(let i = 0; i < this.ELEMENTS; ++i)this[i] -= vector[i];
        return this.check();
    }
    scale(scale) {
        if (typeof scale === "number") for(let i = 0; i < this.ELEMENTS; ++i)this[i] *= scale;
        else for(let i1 = 0; i1 < this.ELEMENTS && i1 < scale.length; ++i1)this[i1] *= scale[i1];