drill rdill dirll idrll ridll irdll drlil rdlil dlril ldril rldil lrdil dilrl idlrl dlirl ldirl ildrl lidrl rildl irldl rlidl lridl ilrdl lirdl drill rdill dirll idrll ridll irdll drlil rdlil dlril ldril rldil lrdil dilrl idlrl dlirl ldirl ildrl lidrl rildl irldl rlidl lridl ilrdl lirdl drlli rdlli dlrli ldrli rldli lrdli drlli rdlli dlrli ldrli rldli lrdli dllri ldlri dllri ldlri lldri lldri rlldi lrldi rlldi lrldi llrdi llrdi dillr idllr dlilr ldilr ildlr lidlr dillr idllr dlilr ldilr ildlr lidlr dllir ldlir dllir ldlir lldir lldir illdr lildr illdr lildr llidr llidr rilld irlld rlild lrild ilrld lirld rilld irlld rlild lrild ilrld lirld rllid lrlid rllid lrlid llrid llrid illrd lilrd illrd lilrd llird llird
Note: these 'words' (valid or invalid) are all the permutations of the word drill. These words are obtained by scrambling the letters in drill.