HurdAudio blogs about a recording of Terry Riley keyboard music by Steffen Schleiermacher:
Electronically aided interpretations of the early Terry Riley compositions as a labor of love. A love of the static textures and pulsating beauty that erupts through the fine details of repeated patterns sliding apart from one another.
I have numerous Terry Riley recordings and numerous Steffen Schleiermacher recordings and somehow, I know nothing of the intersection of these two fine artists.
A quick check shows these are not readily available for download from emusic or Amazon (although on CD from the latter). And highlighting yet another hole in my collection, Amazon also has a different CD of Riley keyboard music, this time by the Italian Fabrizio Ottaviucci.
Keyboard Study no. 1 was also called Coule; the title is a pun on the French word for 'flowing' or 'gliding' (or in musical terminology, the 'slur' as a phrase marking), and Riley pronounces it, as though without its acute accent. 'Cool', a term of colloquial approbation still new when the piece was first conceived.
YouTube has a video that presumably uses the music from one of these recordings: