content: CONFUSED Microsoft has nothing to do with the amazing Visicalc. Visicalc was ripped off by total rewrite as MultiPlan and needed a z80 co-processor card on the Apple II's. Microsoft hired a GENIUS who among other things headed MS Excel, a successor to his own  Microsoft Multiplan. https://en.wikipedia.org/wiki/Charles_Simonyi Visicalc was never open source, nor were MS multiplan, nor MS excel All three made tens of millions of dollars each.