Many years ago, a good friend gave me a torn-out photocopy excerpt from Stanislaw Lem's *Cyberiad*. Entitled "Love and Tensor Algebra", it's an entry to an electronic poetry competition, authored by a "computer laureate".

It surfaced partway through a start-of-year filing effort, and it's far too good to resist reproducing it here.

Come, let us hasten to a higher plane,

Where dyads tread the fairy fields of Venn,

Their indices bedecked from one ton,

Commingled in an endless Markov chain!Come, every frustum longs to be a cone,

And every vector dreams of matrices.

Hark to the gentle gradient of the breeze:

It whispers of a more ergodic zone.In Riemann, Hilbert or in Banach space

Let superscripts and subscripts go their ways.

Our asymptotes no longer out of phase,

We shall encounter, counting, face to face.I'll grant thee random access to my heart,

Thou'lt tell me all the constants of thy love;

And so we two shall all love's lemmas prove,

And in our bound partition never part.For what did Cauchy know, or Christoffel,

Or Fourier, or any Boole or Euler,

Wielding their compasses, their pens and rulers,

Of thy supernal sinusoidal spell?Cancel me not -- for what then shall remain?

Abscissas some mantissas, modules, modes,

A root or two, a torus and a node:

The inverse of my verse, a null domain.Ellipse of bliss, converge, O lips divine!

The product of four scalars it defines!

Cyberiaddraws nigh, and the skew mind

Cuts capers like a happy haversine.I see the eigenvalue in thine eye,

I hear the tender tensor in thy sigh.

Bernoulli would have been content to die,

Had he but known sucha!^{2}cos 2ϕ

Two questions occurred to me after I found it: *what on earth is a haversine?*, and: *why is this excerpt both photocopied and torn out*?