 the effect that there
was &quot;some kind of algebra or logic to the operations on parentheses
that is more basic than the algebra of operations on the letters and
numbers&quot;.  The summer I left for college, in 1967, I wrote down a list
of a dozen or so &quot;things to think about&quot;, and this problem figured high
on that list.

I first started thinking about computers, graphs, and logic
all in the same breath sometime toward the end of that year,
when I tried to put the Fortran that I was learning i