A long-time favorite! For me, Riley's more minimalist works are hit or miss - I've loved a few, but the more widely famed few like In C leave me cold.
Anyhow, this is different. Maybe 70% of its DNA is in traditional Spanish music(s), especially flamenco, but with more contemplative and even "dark" stretches and not so much the feverishly fast flamenco flourishes. And then it's pushed beyond or aside or over or under the previous boundaries, with various wrinkles of structure or instrumentation (guitar + variously violin, assorted percussion, or a second guitar), etc.
And it works beautifully! It's adventurously melodic; it's a ton of fun; it's performed just beautifully, especially by guitarist David Tanenbaum who apparently commissioned the work. Enthusiastically recommended.