On old nautical charts as well as the bird's eye view there is often a coastal profile - the outline of the land seen from the point of view of a sailor approaching it. Radio producer Julian May was struck by the musicality of these, the undulations of hills are melodic, the spacing of landmarks - trees, church spires - rhythmic. Musicians could, he thought, take the line dividing sky from land, place it on manuscript paper, and play the skyline.
Half a dozen prominent musicians are intrigued by this, including jazz musician Courtney Pine; the Scottish composer James MacMillan; Julie Fowlis, leading light of Gaelic song; and Anna Meredith, who was commissioned to create a piece for the Last Night of the Proms.
For Radio 4 Tim Marlow presents three programmes, in England, Wales and Scotland, in which two musicians look at the skyline, talk about their initial responses, then create a piece of music each - playing their skyline. He hears how they are getting along then the musicians, Tim (and Radio 4's listeners) hear for the finished pieces, and consider what they have made.
In the second programme the singer and song writer Kizzy Crawford and pianist Gwilym Simcock create new pieces inspired by the outline against the sky of Port Talbot, seen from the sea. The town, the hills beyond and the steelworks encapsulate the geography and history of Wales.
Kizzy Crawford is eighteen, of Welsh and Bajan heritage, a singer and songwriter at home in English and Welsh. Gwilym Simcock is a Welsh pianist who composes classical pieces, and improvises, too,
They meet Tim Marlow aboard the Seren y Mor (Star of the Sea) looking from out at sea at Port Talbot, whose skyline they will make into music and song.
Producers: Julian May and Benedict Warren.
Play Your Skyline
Why not play your own skyline? Listeners from all over the country and abroad have sent us their compositions. It's simple! Find somewhere that interests you. Draw the line between earth and sky, if you wish, you can trace this onto musical manuscript paper but this isn't essential. Follow the line to create the music of your skyline. Please send a soundfile - mp3 or wav to Playingyourskyline@bbc.co.uk with a picture of the skyline you are playing, and please, no longer than three minutes. We will put some on this website for you to listen to.