pilus iplus plius lpius ilpus lipus piuls ipuls puils upils iupls uipls pluis lpuis pulis uplis lupis ulpis ilups liups iulps uilps luips ulips pilsu iplsu plisu lpisu ilpsu lipsu pislu ipslu psilu spilu isplu siplu plsiu lpsiu psliu spliu lspiu slpiu ilspu lispu islpu silpu lsipu slipu piusl ipusl puisl upisl iupsl uipsl pisul ipsul psiul spiul ispul sipul pusil upsil psuil spuil uspil supil iuspl uispl isupl siupl usipl suipl plusi lpusi pulsi uplsi lupsi ulpsi plsui lpsui pslui splui lspui slpui pusli upsli psuli spuli uspli supli luspi ulspi lsupi slupi uslpi sulpi ilusp liusp iulsp uilsp luisp ulisp ilsup lisup islup silup lsiup sliup iuslp uislp isulp siulp usilp suilp lusip ulsip lsuip sluip uslip sulip
Note: these 'words' (valid or invalid) are all the permutations of the word pilus. These words are obtained by scrambling the letters in pilus.