[spitfire]

Would that be Lotus Improv? I used Improv and Quantrix on NeXTStep. Quantrix on OSX is still a secret weapon of mine.

[bboreham]

I don't think so. They all had code-names - 123 for Windows was Rockport; Improv was Back Bay and the one I'm talking about was another place, but the exact name escapes me.

I believe Improv was written in Objective-C while the one I mean was in C++.

[slededit]

C++ is impressive for 1991. Excel was still K&R C at that time.