netfc entfc ntefc tnefc etnfc tenfc neftc enftc nfetc fnetc efntc fentc ntfec tnfec nftec fntec tfnec ftnec etfnc tefnc eftnc fetnc tfenc ftenc netcf entcf ntecf tnecf etncf tencf nectf enctf ncetf cnetf ecntf centf ntcef tncef nctef cntef tcnef ctnef etcnf tecnf ectnf cetnf tcenf ctenf nefct enfct nfect fnect efnct fenct necft encft nceft cneft ecnft cenft nfcet fncet ncfet cnfet fcnet cfnet efcnt fecnt ecfnt cefnt fcent cfent ntfce tnfce nftce fntce tfnce ftnce ntcfe tncfe nctfe cntfe tcnfe ctnfe nfcte fncte ncfte cnfte fcnte cfnte tfcne ftcne tcfne ctfne fctne cftne etfcn tefcn eftcn fetcn tfecn ftecn etcfn tecfn ectfn cetfn tcefn ctefn efctn fectn ecftn ceftn fcetn cfetn tfcen ftcen tcfen ctfen fcten cften
Note: these 'words' (valid or invalid) are all the permutations of the word netfc. These words are obtained by scrambling the letters in netfc.