"What are you doing," his older brother cried one day, seeing les punching new holes in the player-piano rolls.
“你在做什么，”有一天他的哥哥大喊，因为他看见Les正在给钢琴卷冲压新的孔。
2
It was an unmanned biplane with player-piano bellows to power its gyroscope and a cash-register mechanism that calculated distance flown by counting the rotations of a propeller-like rotor.