dngaf ndgaf dgnaf gdnaf ngdaf gndaf dnagf ndagf dangf adngf nadgf andgf dganf gdanf dagnf adgnf gadnf agdnf ngadf gnadf nagdf angdf gandf agndf dngfa ndgfa dgnfa gdnfa ngdfa gndfa dnfga ndfga dfnga fdnga nfdga fndga dgfna gdfna dfgna fdgna gfdna fgdna ngfda gnfda nfgda fngda gfnda fgnda dnafg ndafg danfg adnfg nadfg andfg dnfag ndfag dfnag fdnag nfdag fndag dafng adfng dfang fdang afdng fadng nafdg anfdg nfadg fnadg afndg fandg dgafn gdafn dagfn adgfn gadfn agdfn dgfan gdfan dfgan fdgan gfdan fgdan dafgn adfgn dfagn fdagn afdgn fadgn gafdn agfdn gfadn fgadn afgdn fagdn ngafd gnafd nagfd angfd ganfd agnfd ngfad gnfad nfgad fngad gfnad fgnad nafgd anfgd nfagd fnagd afngd fangd gafnd agfnd gfand fgand afgnd fagnd
Note: these 'words' (valid or invalid) are all the permutations of the word dngaf. These words are obtained by scrambling the letters in dngaf.