rotate(angle, anchor) {
    const geometries = this.geometries_;
    for (let i = 0, ii = geometries.length; i < ii; ++i) {
      geometries[i].rotate(angle, anchor);
    }
    this.changed();
  }
Rotate the geometry around a given coordinate. This modifies the geometry
coordinates in place.
@param {number} angle Rotation angle in radians.
@param {import("../coordinate.js").Coordinate} anchor The rotation center.
@api
@override