howls ohwls hwols whols owhls wohls holws ohlws hlows lhows olhws lohws hwlos whlos hlwos lhwos wlhos lwhos owlhs wolhs olwhs lowhs wlohs lwohs howsl ohwsl hwosl whosl owhsl wohsl hoswl ohswl hsowl showl oshwl sohwl hwsol whsol hswol shwol wshol swhol owshl woshl oswhl sowhl wsohl swohl holsw ohlsw hlosw lhosw olhsw lohsw hoslw ohslw hsolw sholw oshlw sohlw hlsow lhsow hslow shlow lshow slhow olshw loshw oslhw solhw lsohw slohw hwlso whlso hlwso lhwso wlhso lwhso hwslo whslo hswlo shwlo wshlo swhlo hlswo lhswo hslwo shlwo lshwo slhwo wlsho lwsho wslho swlho lswho slwho owlsh wolsh olwsh lowsh wlosh lwosh owslh woslh oswlh sowlh wsolh swolh olswh loswh oslwh solwh lsowh slowh wlsoh lwsoh wsloh swloh lswoh slwoh
Note: these 'words' (valid or invalid) are all the permutations of the word howls. These words are obtained by scrambling the letters in howls.