By drawing characteristically different parts of a sonata (Allegro, Andante, Scherzo) Ciurlionis rendered variuos gradual motion. He created an entire optical and musical vision from the most imposing elements of nature: rustle of the sea, sparkling of stars, blossom of flowers and trees, flapping of birds...
From the book "XX a. lietuvių dailės istorija" (http://ciurlionis.licejus.lt/T_Saules_son_en.htm)