burfi ubrfi brufi rbufi urbfi rubfi bufri ubfri bfuri fburi ufbri fubri brfui rbfui bfrui fbrui rfbui frbui urfbi rufbi ufrbi furbi rfubi frubi burif ubrif bruif rbuif urbif rubif buirf ubirf biurf iburf uibrf iubrf briuf rbiuf biruf ibruf ribuf irbuf uribf ruibf uirbf iurbf riubf irubf bufir ubfir bfuir fbuir ufbir fubir buifr ubifr biufr ibufr uibfr iubfr bfiur fbiur bifur ibfur fibur ifbur ufibr fuibr uifbr iufbr fiubr ifubr brfiu rbfiu bfriu fbriu rfbiu frbiu brifu rbifu birfu ibrfu ribfu irbfu bfiru fbiru bifru ibfru fibru ifbru rfibu fribu rifbu irfbu firbu ifrbu urfib rufib ufrib furib rfuib fruib urifb ruifb uirfb iurfb riufb irufb ufirb fuirb uifrb iufrb fiurb ifurb rfiub friub rifub irfub firub ifrub
Note: these 'words' (valid or invalid) are all the permutations of the word burfi. These words are obtained by scrambling the letters in burfi.