Since the printer was in the same room, and I was the only person there
(it was about 0300) I was just piping the output of the nroff command
directly to it.

After having successfully done this four or five times, I ran another
nroff command to print the latest copy for proof reading ... then I
waited ... and waited ... and waited.

After about five minutes, this came out on the line printer:

     The world will end!

As you can imagine, this freaked me out just a little.  At that point, I
decided that the last version I had was good enough :-).

It wasn't until about five years later, when I was reading the eqn
manual ... eqn is the filter that formats mathematics for nroff ... and
saw the following:

    "All rows of the matrix must contain the same
     number of columns, or the world will end"