ohrst horst orhst rohst hrost rhost ohsrt hosrt oshrt sohrt hsort short orsht rosht osrht sorht rsoht sroht hrsot rhsot hsrot shrot rshot srhot ohrts horts orhts rohts hrots rhots ohtrs hotrs othrs tohrs htors thors orths roths otrhs torhs rtohs trohs hrtos rhtos htros thros rthos trhos ohstr hostr oshtr sohtr hsotr shotr ohtsr hotsr othsr tohsr htosr thosr osthr sothr otshr toshr stohr tsohr hstor shtor htsor thsor sthor tshor orsth rosth osrth sorth rsoth sroth ortsh rotsh otrsh torsh rtosh trosh ostrh sotrh otsrh tosrh storh tsorh rstoh srtoh rtsoh trsoh stroh tsroh hrsto rhsto hsrto shrto rshto srhto hrtso rhtso htrso thrso rthso trhso hstro shtro htsro thsro sthro tshro rstho srtho rtsho trsho strho tsrho
Note: these 'words' (valid or invalid) are all the permutations of the word ohrst. These words are obtained by scrambling the letters in ohrst.