Listen closely to Radiohead and Hans Zimmer’s rework of “Bloom” for Blue Planet II, and you can hear a really fascinating orchestral trick at work. They call it the “tidal orchestra” — it’s a musical effect created by instructing each player to play their notes only if the person next to them isn’t playing. The result is a randomly swelling and fading musical bed for the entire series that captures the feeling of ocean waves. It’s a captivating way to score a soundtrack for the ocean — but it also fits in with a long history of capturing randomness in music composition.