STEVIE is perhaps my most noteworthy contribution to the Open Source movement, even though the phrase Open Source didn't exist way back in June of 1987 when I posted my little clone of the 'vi' editor to Usenet. STEVIE stood for:

    ST Editor for VI Enthusiasts

and although it was only a subset of real 'vi', it had a good implementation of the 'u' (undo) and '.' (repeat) commands. Here are the two parts of the original posting of STEVIE:

My implementation was usable and good enough for Tony Andrews to take and continue hacking on. A year later in June of 1988, Tony posted this 4-part version of STEVIE to Usenet: Since that time, the software has continuously evolved in the fine tradition of what we now call Open Source, to produce the widely-available and widely-ported editor now known as VIM. I was not involved after my initial development and posting to Usenet, and I didn't really keep track of it after a few years. (I was actually a bit disappointed when the 'u'ndo capability was broken by subsequent development, and was not fixed.)

When I recently discovered that VIM is the great-great-great-great-...-grandson of STEVIE, I was quite suprised and of course very pleased to know that my initial seed was so fruitful. And I was most pleased to see that they fixed the 'u'ndo command and even made it capable of 'infinite undo'.