Much has changed in music since Antonio Vivaldi unveiled his set of four concerti, The Four Seasons, some 300 years ago. Yet composers' awe and fascination for the ecological cycle remains undiminished. Edvard Grieg's To Spring? The Mamas & the Papas' "California Dreamin'"? DJ Jazzy Jeff & The Fresh Prince's "Summertime"? All are paeans to the strange wonder of something as inevitable and elementary as, say, the first warm day of spring, or the humid ecstasy of summer.