Franz Liszt also wrote some very difficult Ã tudes . These two composers ' Ã tudes are known for being not only good for training but beautiful .
Composers of the 20th century variously composed Ã tudes related to the old tradition ( GyÃ rgy Ligeti ) , Ã tudes that required wholly unorthodox technique ( John Cage ) , and Ã tudes that required unusually facile technique .