black lback balck ablck labck albck blcak lbcak bclak cblak lcbak clbak baclk abclk bcalk cbalk acblk cablk lacbk alcbk lcabk clabk aclbk calbk blakc lbakc balkc ablkc labkc albkc blkac lbkac bklac kblac lkbac klbac baklc abklc bkalc kbalc akblc kablc lakbc alkbc lkabc klabc aklbc kalbc blcka lbcka bclka cblka lcbka clbka blkca lbkca bklca kblca lkbca klbca bckla cbkla bkcla kbcla ckbla kcbla lckba clkba lkcba klcba cklba kclba backl abckl bcakl cbakl acbkl cabkl bakcl abkcl bkacl kbacl akbcl kabcl bckal cbkal bkcal kbcal ckbal kcbal ackbl cakbl akcbl kacbl ckabl kcabl lackb alckb lcakb clakb aclkb calkb lakcb alkcb lkacb klacb aklcb kalcb lckab clkab lkcab klcab cklab kclab acklb caklb akclb kaclb ckalb kcalb
Note: these 'words' (valid or invalid) are all the permutations of the word black. These words are obtained by scrambling the letters in black.