YES! YES! Rhuby! That IS it! That quatrain of the Rubaiyat was probably where I was getting my subterranean feel for the word. It was once a big project, to learn the beautiful Rubaiyat by rote, which of course, I never completed, except for a few choice verses.

Here's one that has stayed with me:

AH! My beloved, fill the cup that clears
Today of past regrets and future fears
Tomorrow? Tomorrow I may be
Myself with yesterday's seven thousand years.

Heartfelt thanks Rhuby, for bringing up Khayyam! It took me down many pleasurable alleyways of memory.