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:
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'.