(Sung, of course, to the tune of "99 bottles of beer")

The original is fun the first time you ever hear of it - but within about 3 verses (or less), the charm is gone. Why? Well, it's so predictable. N=N-1, all week long. Or however long it takes to sing it; I don't know, never got very far.

So,
how 'bout mixing it up a little bit? Pick your own equation, something you can graph in 2 dimensions (for the wall's sake), start singing and let everyone else try to figure out what the equation is.

You can place your own limitations - such as "Second order polynomials, and the wall's extents are -100 to 100 on both axes" or "Linear equations, first quadrant only, and answers must be in point-slope form".

For the terminally insomniac, pick a fractal equation and sing yourself to sleep.

Yes, for some equations your meter will need to become asymptotically free-form. Kind of like when you're singing "Happy Birthday" to three or more people.