btfol tbfol bftol fbtol tfbol ftbol btofl tbofl botfl obtfl tobfl otbfl bfotl fbotl boftl obftl fobtl ofbtl tfobl ftobl tofbl otfbl fotbl oftbl btflo tbflo bftlo fbtlo tfblo ftblo btlfo tblfo bltfo lbtfo tlbfo ltbfo bflto fblto blfto lbfto flbto lfbto tflbo ftlbo tlfbo ltfbo fltbo lftbo btolf tbolf botlf obtlf toblf otblf btlof tblof bltof lbtof tlbof ltbof boltf obltf blotf lbotf olbtf lobtf tolbf otlbf tlobf ltobf oltbf lotbf bfolt fbolt boflt obflt foblt ofblt bflot fblot blfot lbfot flbot lfbot bolft oblft bloft lboft olbft lobft folbt oflbt flobt lfobt olfbt lofbt tfolb ftolb toflb otflb fotlb oftlb tflob ftlob tlfob ltfob fltob lftob tolfb otlfb tlofb ltofb oltfb lotfb foltb ofltb flotb lfotb olftb loftb
Note: these 'words' (valid or invalid) are all the permutations of the word btfol. These words are obtained by scrambling the letters in btfol.