block lbock bolck oblck lobck olbck blcok lbcok bclok cblok lcbok clbok boclk obclk bcolk cbolk ocblk coblk locbk olcbk lcobk clobk oclbk colbk blokc lbokc bolkc oblkc lobkc olbkc blkoc lbkoc bkloc kbloc lkboc klboc boklc obklc bkolc kbolc okblc koblc lokbc olkbc lkobc klobc oklbc kolbc blcko lbcko bclko cblko lcbko clbko blkco lbkco bklco kblco lkbco klbco bcklo cbklo bkclo kbclo ckblo kcblo lckbo clkbo lkcbo klcbo cklbo kclbo bockl obckl bcokl cbokl ocbkl cobkl bokcl obkcl bkocl kbocl okbcl kobcl bckol cbkol bkcol kbcol ckbol kcbol ockbl cokbl okcbl kocbl ckobl kcobl lockb olckb lcokb clokb oclkb colkb lokcb olkcb lkocb klocb oklcb kolcb lckob clkob lkcob klcob cklob kclob ocklb coklb okclb koclb ckolb kcolb
Note: these 'words' (valid or invalid) are all the permutations of the word block. These words are obtained by scrambling the letters in block.