brux rbux burx ubrx rubx urbx brxu rbxu bxru xbru rxbu xrbu buxr ubxr bxur xbur uxbr xubr ruxb urxb rxub xrub uxrb xurb
Note: these 'words' (valid or invalid) are all the permutations of the word brux. These words are obtained by scrambling the letters in brux.