crux rcux curx ucrx rucx urcx crxu rcxu cxru xcru rxcu xrcu cuxr ucxr cxur xcur uxcr xucr ruxc urxc rxuc xruc uxrc xurc
Note: these 'words' (valid or invalid) are all the permutations of the word crux. These words are obtained by scrambling the letters in crux.