wltd lwtd wtld twld ltwd tlwd wldt lwdt wdlt dwlt ldwt dlwt wtdl twdl wdtl dwtl tdwl dtwl ltdw tldw ldtw dltw tdlw dtlw
Note: these 'words' (valid or invalid) are all the permutations of the word wltd. These words are obtained by scrambling the letters in wltd.