Computation:
	An infinity of isomorphic metaphors
	for term rewriting.


So there's my first haiku, composed while walking up to collect Jean
from School.

Observations:

 1) I'm not quite sure how to count syllables. And this "5-7-5" rule
 seems poorly observed in examples of haikus I've found online, so
 I've decided to ignore it, and go for an intuitive feeling of balance
 and rhythm rather than any strict rules.

 2) The subject matter is some abstract computer science. See:

    http://en.wikipedia.org/wiki/Term_rewriting
    http://en.wikipedia.org/wiki/Abstract_rewriting_system
    http://en.wikipedia.org/wiki/Formal_system
    http://en.wikipedia.org/wiki/Lambda_calculus
    http://en.wikipedia.org/wiki/Natural_deduction
    http://en.wikipedia.org/wiki/Hoare_logic
    http://en.wikipedia.org/wiki/Operational_semantics
    http://en.wikipedia.org/wiki/Denotational_semantics

 The gist of it, however, is that the process of computation - from
 working out sums or doing calculus or formal logical deduction on pen
 and paper, to a supercomputer predicting the weather or a server farm
 providing a complex Web application to millions of users - can all
 be explained in terms of a mathematical system called "term
 rewriting". Therefore, all these computational processes are, really,
 just metaphors for an underlying term-rewriting activity.