chalk hcalk cahlk achlk haclk ahclk chlak hclak clhak lchak hlcak lhcak calhk aclhk clahk lcahk alchk lachk halck ahlck hlack lhack alhck lahck chakl hcakl cahkl achkl hackl ahckl chkal hckal ckhal kchal hkcal khcal cakhl ackhl ckahl kcahl akchl kachl hakcl ahkcl hkacl khacl akhcl kahcl chlka hclka clhka lchka hlcka lhcka chkla hckla ckhla kchla hkcla khcla clkha lckha cklha kclha lkcha klcha hlkca lhkca hklca khlca lkhca klhca calkh aclkh clakh lcakh alckh lackh caklh acklh ckalh kcalh akclh kaclh clkah lckah cklah kclah lkcah klcah alkch lakch aklch kalch lkach klach halkc ahlkc hlakc lhakc alhkc lahkc haklc ahklc hkalc khalc akhlc kahlc hlkac lhkac hklac khlac lkhac klhac alkhc lakhc aklhc kalhc lkahc klahc
Note: these 'words' (valid or invalid) are all the permutations of the word chalk. These words are obtained by scrambling the letters in chalk.