$ORIGIN tld.

bar 222 IN NS ns.bar.tld.
bar 222 IN NS ns.foo.tld.

ns.bar 11 IN A 127.0.0.1
ns.bar 11 IN AAAA 0:0:0:0:0:0:0:1

ns-only 222 IN NS ns.foo.tld.
ns-only 222 IN NS ns.bar.tld.

ns-and-ds 222 IN NS ns.foo.tld.
ns-and-ds 222 IN NS ns.bar.tld.
ns-and-ds 3333 IN DS 1 2 3 000102