Icelandic composer Ólafur Arnalds was in a hotel lobby somewhere in Asia when he first saw a modern version of a player piano. This particular one was tapping out The Beatles' "Yesterday."

He remembers seeing the machine — something of an updated pianola, the old ones often seen in old Western movies plunking out notes dictated by holes in a roll of paper — and laughing at its function. "I just looked at it and thought, 'OK, that's very silly. That's a very bad idea, but I wonder if there's something there we can work with.'"

However silly, it planted the idea of incorporating technology into his own composing. So, he got together with his code-savvy friend, and together they created a new way to play piano using software.

"It senses what I play. Usually I am sitting at a grand piano, and I would play a chord," he explains from behind his instruments after playing a set at NPR's Tiny Desk. "That chord goes into the software, which manipulates it and then sends it out as rhythmical textures to these two pianos."

Arnald's whole rig consists of two pianos, a laptop loaded with the custom software and Arnalds at the helm with a small keyboard. He plays silent chords on the keyboard, like a remote control of sorts, then the chords are run through the software, and the piano plays a spontaneous array of notes based on the Euclidean algorithm.

It's not simply AI-created music, though. "The idea behind this is not to create a computer that makes music for me, it's to create an instrument that I'm playing," he says.

Instead of hitting one key and getting one note, Arnalds can hit one key and get a multitude of unanticipated notes. That does pose one problem, though: There's no way to replicate what the piano does, which proved difficult in recording his new album re:member, due out Aug. 24. But there's also a spirit of serendipity that comes from it all.

"We're all here, and we're watching a concert that will never be replicated exactly the same," he says from the Desk. "We're all living in this unique moment in time, which will never happen again."

Web intern Emily Abshire contributed to this story.

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