I learned about algebra in the 7th grade. That was a big transition year for me- it was my last year living in Conestoga, my first time in a school where I had a locker and had to move between classrooms every "period", and new challenges of meeting and making friends. There were a lot of structural and social changes that didn't make sense to me.
Our maths instructor was an obese (I thought at the time) old (middle aged, at most) woman with a job to do. She paced the front of the room as if she were a wind-up toy, but one whose authority could not be questioned, and whose performance was well-rehearsed. She introduced us to algebra, a word from Arabic, the purpose of which was never made clear. Are you telling us that there is more to math than addition, subtraction, multiplication and division? Why?
First of all came letters. x, y, z.   a, b, c. These weren't actually letters, they were called variables. They came in equations. We were to learn how to solve for them. I couldn't see the point, but I got along with them for a while- until quadratic equations. These involved things that resembled fractions, only with letters in them. I had enough trouble already with the concept of fractions, I didn't really need this added aggravation. I had always been an able student (except for that time when I couldn't memorize my times tables, but that's another story) and I got very frustrated with this algebra stuff, even failing quizzes for the first time in my life. Oh the shame!
But then, a miracle. These letters we had been using were not like numbers, which to my way of thinking had very distinct places in an order. I suddenly understood that these were called variables for a reason. Their value could literally vary- they could be anything! I know, it was the simplest thing imaginable, which was probably why my teacher had so much trouble explaining it to me. Once I got this into my head, algebra was great! All the tricks you could do to eliminate unknowns from equations made this an elaborate game.
(If I were king, variables would have their own symbols- they would not be letters, which have enough work to do carrying meaning in writing. It would be a lot of fun creating unique shapes and coming up with names for a family of symbols to be used as variables, and someday I may give it a shot. I really like doing that sort of thing. But right now there's a song to discuss.)
Love is like algebra, and what I mean by this is that, for all we believe we know about it, about how it affects us, about how it ebbs and flows, appears and disappears, and even sometimes becomes its opposite, we don't always "get" a very simple and basic thing about it. That thing is like the variable, it can be anything at all, and it changes as other factors change. And it's really troubling when those changing factors are things we had assumed were constants.
This is a very fertile place to start from when your intention is to write a song about love. I first got this idea from a girl I had strong feelings for, a young woman who really liked maths. The song started out being called She Loves Algebra, and was going to be a sort of Fountains of Wayne kind of thing.
But then the song morphed into something deeper, and became about the very nature of love. I had a lot of fun working in references to Spain, for us English speakers the place of origin of algebra, also legendary for hot-blooded romance. An interesting combination!
Loves Algebra
One I love
Come to me
I'll bring you oranges, blossoms of roses,
And moonlight on the sea

There may be no reason
No time and no season
In love's Algebra

Close your eyes
And let the dream begin
Dream of the birds whose songs are the words
"Love has come again"

If you need persuasion
Look for our equation
In love's Algebra

Rules there are
And sweet unknowns
Places beyond which your heart hasn't gone
We'll make them our own

Given resolution
You'll find your solution
In love's Algebra

Now I want to finish writing the earlier version.
what lies beneath