docs: function transformArc(arc, scale, translate) {
    let x = 0;
    let y = 0;
    for (let i = 0, ii = arc.length; i < ii; ++i) {
      const vertex = arc[i];
      x += vertex[0];
      y += vertex[1];
      vertex[0] = x;
      vertex[1] = y;
      transformVertex(vertex, scale, translate);
    }
  }