Elizabeth D Rather wrote:

This kind of reminds me of years ago when I would look for differences
by printing on cheap (thin) printer paper, laying one on the other, and
holding it up to the window to see the differences. Primitive, but
effective. And not unlike what I still end up having to do with most
schematic capture applications (most can give you a difference in a
netlist, but if you want to graphically see what's different, the best
you can do with most of the packages I've used is to have two windows
and toggle between them).

Regardless, thanks for the historical account. It sounds like the core
of what you were doing was having N copies of the application blocks
stored elsewhere on your block storage which is both simple and obvious.

Part of what I'm trying to see (aside from my usual interest in computer
history) is what kinds of trade-offs different approaches took, and in
particular approaches used to support multiple developers instead of a
lone developer. All this is being used as research for a new project at
work with some unusual requirements that might lend itself to
block-style development directly on the target.