upbye pubye ubpye bupye pbuye bpuye upybe puybe uypbe yupbe pyube ypube ubype buype uybpe yubpe byupe ybupe pbyue bpyue pybue ypbue bypue ybpue upbey pubey ubpey bupey pbuey bpuey upeby pueby uepby eupby peuby epuby ubepy buepy uebpy eubpy beupy ebupy pbeuy bpeuy pebuy epbuy bepuy ebpuy upyeb puyeb uypeb yupeb pyueb ypueb upeyb pueyb uepyb eupyb peuyb epuyb uyepb yuepb ueypb euypb yeupb eyupb pyeub ypeub peyub epyub yepub eypub ubyep buyep uybep yubep byuep ybuep ubeyp bueyp uebyp eubyp beuyp ebuyp uyebp yuebp ueybp euybp yeubp eyubp byeup ybeup beyup ebyup yebup eybup pbyeu bpyeu pybeu ypbeu bypeu ybpeu pbeyu bpeyu pebyu epbyu bepyu ebpyu pyebu ypebu peybu epybu yepbu eypbu byepu ybepu beypu ebypu yebpu eybpu
Note: these 'words' (valid or invalid) are all the permutations of the word upbye. These words are obtained by scrambling the letters in upbye.