Lotus 1-2-3 on the PC w/DOS
https://stonetools.ghost.io/lotus123-dos/
VisiCalc started it, but 1-2-3 finished it. "It" being the discussion of what a spreadsheet can be, and also VisiCalc itself.
<- this is fun, but it is basically "a millennial discovers what you could do with 1-2-3 before they were born, and is blown away."
