3 things i have learnt about nvi today:

a) There are _number_ buffers that hold the nth last yanked/deleted text (that included newlines): "3p pastes the 3rd most recent thing you deleted (this one applies to vi and is thanks to Learning the Vi Editor by Linda Lamb);
b) nvi faithfully implements a second u undoing the first u, therefore making a 2-cycle undo/redo loop; but, a . after a u undoes older and older edits! (thanks to a random blog post);
c) the :script sh ex command is like emacs subshell-buffers, except without the convenience of editing with emacs bindings. Surreal. (thanks to unearthing ancient pty calls in the source code)

#vi