tetra ettra ttera ttera ettra tetra terta etrta treta rteta ertta retta ttrea ttrea trtea rttea trtea rttea etrta terta ertta retta treta rteta tetar ettar ttear ttear ettar tetar teatr etatr taetr atetr eattr aettr ttaer ttaer tater atter tater atter etatr teatr eattr aettr taetr atetr terat etrat treat rteat ertat retat teart etart taert atert eatrt aetrt traet rtaet taret atret ratet artet eratt reatt eartt aertt raett arett ttrae ttrae trtae rttae trtae rttae ttare ttare tatre attre tatre attre trate rtate tarte atrte ratte artte trate rtate tarte atrte ratte artte etrat terat ertat retat treat rteat etart teart eatrt aetrt taert atert eratt reatt eartt aertt raett arett traet rtaet taret atret ratet artet
Note: these 'words' (valid or invalid) are all the permutations of the word tetra. These words are obtained by scrambling the letters in tetra.