ruddy urddy rdudy drudy udrdy durdy ruddy urddy rdudy drudy udrdy durdy rdduy drduy rdduy drduy ddruy ddruy uddry dudry uddry dudry ddury ddury rudyd urdyd rduyd druyd udryd duryd ruydd urydd ryudd yrudd uyrdd yurdd rdyud dryud rydud yrdud dyrud ydrud udyrd duyrd uydrd yudrd dyurd ydurd rudyd urdyd rduyd druyd udryd duryd ruydd urydd ryudd yrudd uyrdd yurdd rdyud dryud rydud yrdud dyrud ydrud udyrd duyrd uydrd yudrd dyurd ydurd rddyu drdyu rddyu drdyu ddryu ddryu rdydu drydu ryddu yrddu dyrdu ydrdu rdydu drydu ryddu yrddu dyrdu ydrdu ddyru ddyru dydru yddru dydru yddru uddyr dudyr uddyr dudyr dduyr dduyr udydr duydr uyddr yuddr dyudr ydudr udydr duydr uyddr yuddr dyudr ydudr ddyur ddyur dydur yddur dydur yddur
Note: these 'words' (valid or invalid) are all the permutations of the word ruddy. These words are obtained by scrambling the letters in ruddy.