There are many visual symbols of musical notes and melody dancing in Ruei-suei Elementary School. The work, Concert in the Field, is designed not only to have visual echo with those symbols but also to provide surrounded sound perception for the audience. By stepping on the keys, the work can make the sound of the piano, and when the audience passes by, it makes the sound as frogs singing. We expect to bring the natural lovely sound of frogs back to our memory.