It's a grid of Youtube videos, each of someone playing a musical instrument of various sorts (electric guitar, piano, clarinet, marimba, muted trumpet, voice, KAOSS synth pad, a Nintendo DS), making music in the key of B-flat major. The instructions are to start the videos at any time and in any order. By doing so, the audio of each overlays each other and since they are all in tune with each other, it all sounds like the timing could have been intentional. Each video is about 90 seconds long and you can press play again on each to repeat it if you like.
It reminds me (presumably intentionally) of Terry Riley's "In C" in which any number of musicians on any instruments perform together on stage. All following the same tempo, they each have a set of music giving several dozen short sequences of notes. They each, individually, decide when to come in, how many times to repeat each sequence, and when to move on to the next sequence. As the piece continues, the soundscape is constantly evolving in an unpredictable way, but always in tune with each other and pleasant in its harmony. Each time it's performed, even by all the same musicians, then, it sounds different, yet the same. It's a really fascinating piece and if you get the chance to see it performed live, I highly recommend it, because it's a lot of fun to watch the musicians themselves experience the performance and feed off each other.
Thanks for your insightful answer. I've long been a fan of In C and various performances so I'll certainly be looking forward to experiencing this tonight.
On my Pixel 6A + Firefox it says it doesn't run but runs fine if I click through the dialog.
It's a grid of youtube embeds linking videos of people playing simple, improvised sequences in Bb on different instruments. They can be played in different orders, combinations and overlaps to create different textures.
It is a grid of embedded YouTube videos, each one of which including "in B-flat" or "in Bb" in the title (and so are pretty much all someone playing some random song on some random instrument... in B-flat).
It reminds me (presumably intentionally) of Terry Riley's "In C" in which any number of musicians on any instruments perform together on stage. All following the same tempo, they each have a set of music giving several dozen short sequences of notes. They each, individually, decide when to come in, how many times to repeat each sequence, and when to move on to the next sequence. As the piece continues, the soundscape is constantly evolving in an unpredictable way, but always in tune with each other and pleasant in its harmony. Each time it's performed, even by all the same musicians, then, it sounds different, yet the same. It's a really fascinating piece and if you get the chance to see it performed live, I highly recommend it, because it's a lot of fun to watch the musicians themselves experience the performance and feed off each other.
Check out this YouTube search for a variety of live performances: https://www.youtube.com/results?search_query=in+c+live