swith wsith siwth iswth wisth iwsth swtih wstih stwih tswih wtsih twsih sitwh istwh stiwh tsiwh itswh tiswh witsh iwtsh wtish twish itwsh tiwsh swiht wsiht siwht iswht wisht iwsht swhit wshit shwit hswit whsit hwsit sihwt ishwt shiwt hsiwt ihswt hiswt wihst iwhst whist hwist ihwst hiwst swthi wsthi stwhi tswhi wtshi twshi swhti wshti shwti hswti whsti hwsti sthwi tshwi shtwi hstwi thswi htswi wthsi twhsi whtsi hwtsi thwsi htwsi sithw isthw stihw tsihw itshw tishw sihtw ishtw shitw hsitw ihstw histw sthiw tshiw shtiw hstiw thsiw htsiw ithsw tihsw ihtsw hitsw thisw htisw withs iwths wtihs twihs itwhs tiwhs wihts iwhts whits hwits ihwts hiwts wthis twhis whtis hwtis thwis htwis ithws tihws ihtws hitws thiws htiws
Note: these 'words' (valid or invalid) are all the permutations of the word swith. These words are obtained by scrambling the letters in swith.