This last
thing I need help with. It looks to be about 20+ years old
but I could be wrong...
It is bright red, almost perfectly round, has
a steel ball as the roller, 3 black switches, and says "5271" and then
"DEPRAZ - MOUSE" on the bottom.
That mouse model was used with the AT&T/Teletype 5620 DMD terminal, the
commercial version of Rob Pike's "BLIT". Probably used for other stuff
as well.