bills iblls blils lbils ilbls libls bills iblls blils lbils ilbls libls bllis lblis bllis lblis llbis llbis illbs lilbs illbs lilbs llibs llibs bilsl iblsl blisl lbisl ilbsl libsl bisll ibsll bsill sbill isbll sibll blsil lbsil bslil sblil lsbil slbil ilsbl lisbl islbl silbl lsibl slibl bilsl iblsl blisl lbisl ilbsl libsl bisll ibsll bsill sbill isbll sibll blsil lbsil bslil sblil lsbil slbil ilsbl lisbl islbl silbl lsibl slibl bllsi lblsi bllsi lblsi llbsi llbsi blsli lbsli bslli sblli lsbli slbli blsli lbsli bslli sblli lsbli slbli llsbi llsbi lslbi sllbi lslbi sllbi illsb lilsb illsb lilsb llisb llisb ilslb lislb isllb sillb lsilb slilb ilslb lislb isllb sillb lsilb slilb llsib llsib lslib sllib lslib sllib
Note: these 'words' (valid or invalid) are all the permutations of the word bills. These words are obtained by scrambling the letters in bills.