SNOW PIECE (1963)
Think that snow is falling. Think that snow is falling everywhere all the time. When you talk with a person, think that snow is falling between you and on the person. Stop conversing when you think the person is covered by snow...
A PIECE FOR ORCHESTRA (1962)
Count all the stars of that night by heart. The piece ends when all the orchestra members finish counting the stars, or when it dawns. This can be done with windows instead of stars.