We pick j.root-servers.net, one of the 13 root servers (1), and ask it about ns0.punchdown.org and learn that org is delegated to six name servers (2), so we ask a2.org.afilias-nst.info where we learn that punchdown.org is delegated to two name servers, including ns1.punchdown.net (3), so we ask that one and get the following answer: