In Debussy's preludes for piano, there is the number 5 entitled "les collines d'anacapri". It comprises the following Time Signature. One that I have never seen before, and was wondering what it meant?
A bar of 12/16, a bar of 2/4, a bar of 12/16, a bar of 2/4... '+' would be more usual. I imagine '=' indicates the bars are of equal duration.
However, I've seen it stated that "The "critical notes" to the Wiener Urtext publication of this prelude pretty much acknowledge that Debussy's notation for this piece is an inconsistent mess."