fetal eftal fteal tfeal etfal tefal featl efatl faetl afetl eaftl aeftl ftael tfael fatel aftel tafel atfel etafl teafl eatfl aetfl taefl atefl fetla eftla ftela tfela etfla tefla felta eflta fleta lfeta elfta lefta ftlea tflea fltea lftea tlfea ltfea etlfa telfa eltfa letfa tlefa ltefa fealt efalt faelt afelt eaflt aeflt felat eflat fleat lfeat elfat lefat falet aflet flaet lfaet alfet lafet ealft aelft elaft leaft aleft laeft ftale tfale fatle aftle tafle atfle ftlae tflae fltae lftae tlfae ltfae falte aflte flate lfate alfte lafte talfe atlfe tlafe ltafe altfe latfe etalf tealf eatlf aetlf taelf atelf etlaf telaf eltaf letaf tleaf lteaf ealtf aeltf elatf leatf aletf laetf talef atlef tlaef ltaef altef latef
Note: these 'words' (valid or invalid) are all the permutations of the word fetal. These words are obtained by scrambling the letters in fetal.