(Devarim 6:9) "And you shall write them ("uchetavtem")": distinct writing, ("uchetavtem" suggesting "ketivah tamah" ["whole writing"]). From here they ruled: If he wrote alef (looking like) ayin; ayin like aleph; bet like kaf; kaf like bet; gimmel like tzaddik; tzaddik like gimmel; dalet like resh; resh like dalet; heh like chet; chet like heh; vav like yod; yod like vav; zayin like nun; nun like zayin; teth like peh; peh like teth; curved letters like straight ones; straight ones like curved ones; mem like samech; samech like mem; closed ones like open ones; open ones like closed ones; a closed section like an open one; an open one like a closed one — or (if he wrote running text) like a song or song like a running text, or if he wrote without ink, or if he wrote the Divine names in gold — these are to be secreted.