krubi rkubi kurbi ukrbi rukbi urkbi krbui rkbui kbrui bkrui rbkui brkui kubri ukbri kburi bkuri ubkri bukri rubki urbki rbuki bruki ubrki burki kruib rkuib kurib ukrib rukib urkib kriub rkiub kirub ikrub rikub irkub kuirb ukirb kiurb ikurb uikrb iukrb ruikb urikb riukb irukb uirkb iurkb krbiu rkbiu kbriu bkriu rbkiu brkiu kribu rkibu kirbu ikrbu rikbu irkbu kbiru bkiru kibru ikbru bikru ibkru rbiku briku ribku irbku birku ibrku kubir ukbir kbuir bkuir ubkir bukir kuibr ukibr kiubr ikubr uikbr iukbr kbiur bkiur kibur ikbur bikur ibkur ubikr buikr uibkr iubkr biukr ibukr rubik urbik rbuik bruik ubrik burik ruibk uribk riubk irubk uirbk iurbk rbiuk briuk ribuk irbuk biruk ibruk ubirk buirk uibrk iubrk biurk iburk
Note: these 'words' (valid or invalid) are all the permutations of the word krubi. These words are obtained by scrambling the letters in krubi.