The symbols on different lines represent the different pitches of the sounds such as do rei mi fa so la ti; the symbols of different shapes express the different lengths of the sounds. There are also other symbols such as lines and logos that express legato, stress, pauses, etc. and the expressiveness of music.

Give you a children's song: graphically illustrate the length of the sounds expressed by different note symbols.

The round egg sings four beats;

The racket sings three beats with added dots,

Only the racket sings two beats,

Little Tadpoles sing a beat.