This package is a playground full of comonadic folds.
This style of fold is documented in
Automata, Part II: PNGs and Moore">
This package can be seen as what happens if you chase Max Rabkin's
<http://squing.blogspot.com/2008/11/beautiful-folding.html "Beautiful Folding">
to its logical conclusion.
More information on this approach can be found in the
"Another lovely example of type class morphisms"> and
<http://conal.net/blog/posts/more-beautiful-fold-zipping "More beautiful fold
zipping"> posts by Conal Elliott, as well as in Gabriel Gonzales'
"Composable Streaming Folds">.