ruffs urffs rfufs frufs ufrfs furfs ruffs urffs rfufs frufs ufrfs furfs rffus frfus rffus frfus ffrus ffrus uffrs fufrs uffrs fufrs ffurs ffurs rufsf urfsf rfusf frusf ufrsf fursf rusff ursff rsuff sruff usrff surff rfsuf frsuf rsfuf srfuf fsruf sfruf ufsrf fusrf usfrf sufrf fsurf sfurf rufsf urfsf rfusf frusf ufrsf fursf rusff ursff rsuff sruff usrff surff rfsuf frsuf rsfuf srfuf fsruf sfruf ufsrf fusrf usfrf sufrf fsurf sfurf rffsu frfsu rffsu frfsu ffrsu ffrsu rfsfu frsfu rsffu srffu fsrfu sfrfu rfsfu frsfu rsffu srffu fsrfu sfrfu ffsru ffsru fsfru sffru fsfru sffru uffsr fufsr uffsr fufsr ffusr ffusr ufsfr fusfr usffr suffr fsufr sfufr ufsfr fusfr usffr suffr fsufr sfufr ffsur ffsur fsfur sffur fsfur sffur
Note: these 'words' (valid or invalid) are all the permutations of the word ruffs. These words are obtained by scrambling the letters in ruffs.