shaft hsaft sahft ashft hasft ahsft shfat hsfat sfhat fshat hfsat fhsat safht asfht sfaht fsaht afsht fasht hafst ahfst hfast fhast afhst fahst shatf hsatf sahtf ashtf hastf ahstf shtaf hstaf sthaf tshaf htsaf thsaf sathf asthf stahf tsahf atshf tashf hatsf ahtsf htasf thasf athsf tahsf shfta hsfta sfhta fshta hfsta fhsta shtfa hstfa sthfa tshfa htsfa thsfa sftha fstha stfha tsfha ftsha tfsha hftsa fhtsa htfsa thfsa fthsa tfhsa safth asfth sfath fsath afsth fasth satfh astfh stafh tsafh atsfh tasfh sftah fstah stfah tsfah ftsah tfsah aftsh fatsh atfsh tafsh ftash tfash hafts ahfts hfats fhats afhts fahts hatfs ahtfs htafs thafs athfs tahfs hftas fhtas htfas thfas fthas tfhas afths faths atfhs tafhs ftahs tfahs
Note: these 'words' (valid or invalid) are all the permutations of the word shaft. These words are obtained by scrambling the letters in shaft.