How to convert RxJS triple ‘of(…).pipe.map(…)’ expression to the Observable of three dimensional array

I have this expression:

var s2 = of(6, 16, 26).pipe(
    map(v1=>of(5, 15, 25).pipe(
      map(v2=>[v1,v2])
      )), 
    combineLatestAll());
  s2.subscribe(console.log)

… and s2 is an of type Observable<number[][]>as I want it.

Can I convert the following expression in a similar way to Observable<number[][][]> (instead of it being an Observable<Observable<number[]>[]>):

var r2 = of(5, 15, 25).pipe(
    map(v1=>of(6, 16, 26).pipe(
      map(v2=>of(7, 17, 27).pipe(
        map(v3 => [v1,v2,v3])
        )))),
    combineLatestAll());

I can’t get my head around it. Any help appreciated.