Once or twice a decade it seems, country makes big inroads into the pop charts. I was lucky enough to be surrounded by records and radio pretty much everywhere during the ’70s, when it happened twice — with great results.

One of those was Willie Nelson’s 1978 classic, Stardust. The album was a collection of his deceptively simple-seeming takes on American songbook staples like “All Of Me,” “Moonlight In Vermont,” “Don’t Get Around Much Anymore,” and of course the title track.

Tonight’s pick, Irving Berlin’s “Blue Skies,” appeared in my head as an earworm the other night when I was settling down into bed. I had my iPad on my lap and my earbuds in my ears, so I pulled up the song on YouTube and let it go. When you’re relaxed and can really listen to a song, you notice things you might not have before. In this case, not in over 35 years of listening to a song.

It’s nicely layered (I wish I knew who arranged it), and doesn’t waste any time establishing them. A few guitar chords and then the piano kicks in followed quickly by the strings and harmonica. Barely 11 seconds have gone by before Nelson’s gentle vocal begins and you know you’re in for something special. But what I noticed the other night is there’s sort of a rhythmic tension between the three main layers of the arrangement — vocal, main orchestration, and strings.

That tension adds excitement, almost drama, to a simple sunny song about a summer sky. Or maybe it was just my imagination getting away from me on a soft bed under dim lights at a late hour.

But something has kept people listening to this one for nearly four decades, and maybe that’s it.