nbhca bnhca nhbca hnbca bhnca hbnca nbcha bncha ncbha cnbha bcnha cbnha nhcba hncba nchba cnhba hcnba chnba bhcna hbcna bchna cbhna hcbna chbna nbhac bnhac nhbac hnbac bhnac hbnac nbahc bnahc nabhc anbhc banhc abnhc nhabc hnabc nahbc anhbc hanbc ahnbc bhanc hbanc bahnc abhnc habnc ahbnc nbcah bncah ncbah cnbah bcnah cbnah nbach bnach nabch anbch banch abnch ncabh cnabh nacbh ancbh canbh acnbh bcanh cbanh bacnh abcnh cabnh acbnh nhcab hncab nchab cnhab hcnab chnab nhacb hnacb nahcb anhcb hancb ahncb ncahb cnahb nachb anchb canhb acnhb hcanb chanb hacnb ahcnb cahnb achnb bhcan hbcan bchan cbhan hcban chban bhacn hbacn bahcn abhcn habcn ahbcn bcahn cbahn bachn abchn cabhn acbhn hcabn chabn hacbn ahcbn cahbn achbn
Note: these 'words' (valid or invalid) are all the permutations of the word nbhca. These words are obtained by scrambling the letters in nbhca.