Exploring the impact that Estonian composer Arvo Pärt's piece for piano and violin Spiegel im Spiegel has had on people's lives.

Exploring the impact that Estonian composer Arvo Pärt's piece for piano and violin Spiegel im Spiegel has had on people's lives.

Written in 1978, just prior to his departure from Estonia, Arvo Pärt's Spiegel im Spiegel is musically minimal, yet produces a serene tranquillity.

It's in F major in 6/4 time, with the piano playing rising crotchet triads and the violin playing slow scales, alternately rising and falling, of increasing length, which all end on the note A. The score of the piece looks deceptively simple, but as violinist, Tasmin Little explains, it's one of the most difficult pieces to perform because the playing has to simply be perfect, or the mood is lost.

"Spiegel im Spiegel" in German literally can mean both "mirror in the mirror" as well as "mirrors in the mirror", referring to the infinity of images produced by parallel plane mirrors.

The programme contains an interview with visual artist Mary Husted who heard this work and was inspired to produce a set of collages called "Spiegel im Spiegel" which in a round about way, led to her long lost son tracing her for the first time in his life.