Thanks for HexFiend man! I use several times a week.
The killer app was not Lotus 1-2-3 v2, but Turbo Pascal w/ 8087 support. It screamed through tensors and 3D spaces, places we only saw on plotters.
It was not until I got a G3 and used Graphing calculator that I could explore sombrero functions of increasing frequency.
Floating point math is essential, not an option.