The return of the analog computer?

The return of the analog computer?  Sort of.  I worked on (as a maintenance tech) electro-mechanical analog fire control computers in the Navy.  Those computers did integration and differentiation with gears, and arbitrary functions with cams.  They were computers that could give you the wrong answer if you didn't keep them clean and lubricated.  They were also far more interesting to watch work than a modern digital computer :)