Arvo Pärt (1935-)  is an Estonian composer.  The majority of his musical works are choral pieces.  He has also composed short instrumental pieces.  His music is simple but very beautiful.

Spiegel im Spiegel (mirror in a mirror) is a very simple and touching piece for violin and piano.  It has also been arranged for cello and piano.

Here is a recording of Spiegel Im Spiegel (Violin And Piano):

The recording begins at 0:37.