ridlt irdlt rdilt drilt idrlt dirlt rildt irldt rlidt lridt ilrdt lirdt rdlit drlit rldit lrdit dlrit ldrit idlrt dilrt ildrt lidrt dlirt ldirt ridtl irdtl rditl dritl idrtl dirtl ritdl irtdl rtidl tridl itrdl tirdl rdtil drtil rtdil trdil dtril tdril idtrl ditrl itdrl tidrl dtirl tdirl riltd irltd rlitd lritd ilrtd lirtd ritld irtld rtild trild itrld tirld rltid lrtid rtlid trlid ltrid tlrid iltrd litrd itlrd tilrd ltird tlird rdlti drlti rldti lrdti dlrti ldrti rdtli drtli rtdli trdli dtrli tdrli rltdi lrtdi rtldi trldi ltrdi tlrdi dltri ldtri dtlri tdlri ltdri tldri idltr diltr ildtr lidtr dlitr lditr idtlr ditlr itdlr tidlr dtilr tdilr iltdr litdr itldr tildr ltidr tlidr dltir ldtir dtlir tdlir ltdir tldir
Note: these 'words' (valid or invalid) are all the permutations of the word ridlt. These words are obtained by scrambling the letters in ridlt.