shreb hsreb srheb rsheb hrseb rhseb sherb hserb sehrb eshrb hesrb ehsrb srehb rsehb serhb esrhb reshb ershb hresb rhesb hersb ehrsb rehsb erhsb shrbe hsrbe srhbe rshbe hrsbe rhsbe shbre hsbre sbhre bshre hbsre bhsre srbhe rsbhe sbrhe bsrhe rbshe brshe hrbse rhbse hbrse bhrse rbhse brhse shebr hsebr sehbr eshbr hesbr ehsbr shber hsber sbher bsher hbser bhser sebhr esbhr sbehr bsehr ebshr beshr hebsr ehbsr hbesr bhesr ebhsr behsr srebh rsebh serbh esrbh resbh ersbh srbeh rsbeh sbreh bsreh rbseh brseh sebrh esbrh sberh bserh ebsrh besrh rebsh erbsh rbesh bresh ebrsh bersh hrebs rhebs herbs ehrbs rehbs erhbs hrbes rhbes hbres bhres rbhes brhes hebrs ehbrs hbers bhers ebhrs behrs rebhs erbhs rbehs brehs ebrhs berhs
Note: these 'words' (valid or invalid) are all the permutations of the word shreb. These words are obtained by scrambling the letters in shreb.