$ ls -ld /dir-lev1
drwxrwxr-x. 25 sgroup sgroup 4096 Feb 27 09:06 /dir-lev1

$ ls -ld /dir-lev1/dir-lev2
drwx------. 3 root root 4096 May 17 16:29 /dir-lev1//dir-lev2

$ mkdir mydir
$ chmod a+t mydir

chmod 1777 mydir

$ touch testfile.txt
$ chmod u+s testfile.txt