coffs ocffs cfofs fcofs ofcfs focfs coffs ocffs cfofs fcofs ofcfs focfs cffos fcfos cffos fcfos ffcos ffcos offcs fofcs offcs fofcs ffocs ffocs cofsf ocfsf cfosf fcosf ofcsf focsf cosff ocsff csoff scoff oscff socff cfsof fcsof csfof scfof fscof sfcof ofscf foscf osfcf sofcf fsocf sfocf cofsf ocfsf cfosf fcosf ofcsf focsf cosff ocsff csoff scoff oscff socff cfsof fcsof csfof scfof fscof sfcof ofscf foscf osfcf sofcf fsocf sfocf cffso fcfso cffso fcfso ffcso ffcso cfsfo fcsfo csffo scffo fscfo sfcfo cfsfo fcsfo csffo scffo fscfo sfcfo ffsco ffsco fsfco sffco fsfco sffco offsc fofsc offsc fofsc ffosc ffosc ofsfc fosfc osffc soffc fsofc sfofc ofsfc fosfc osffc soffc fsofc sfofc ffsoc ffsoc fsfoc sffoc fsfoc sffoc
Note: these 'words' (valid or invalid) are all the permutations of the word coffs. These words are obtained by scrambling the letters in coffs.