Via Patrick Logan, a funny little bit in a Software Development article on older languages:

"This trip down memory lane was inspired by Dan Weinreb, who wrote regarding a passing comment I'd made in 'Playing by the Rules' (Interface, Aug. 2001) about the 'true believers' who wrote spreadsheets in Lisp--not realizing that anyone actually had done so. In 1981, Weinreb worked at the MIT Artificial Intelligence lab, and his girlfriend worked for the folks who wrote VisiCalc. Using the MIT Lisp machine, he wrote an implementation of VisiCalc in Lisp, and improved the commercial product by utilizing the mouse (which at that time was not in widespread use on PCs). He writes, 'I did it just to show how easy it was to write VisiCalc if you already have Lisp plus a graphics library and window system--though I'm sure Dan Bricklin and Bob Frankston (cocreators of VisiCalc) were perfectly aware of this.'"