-`tz`, which accomplished the task by mapping a char list zipper to a
-char list. We'll call the two parts of the zipper `unzipped` and
-`zipped`; we start with a fully zipped list, and move elements to the
-zipped part by pulling the zipped down until the zipped part is empty.
+`tz` (for task with zippers), which accomplishes the task by mapping a
+char list zipper to a char list. We'll call the two parts of the
+zipper `unzipped` and `zipped`; we start with a fully zipped list, and
+move elements to the zipped part by pulling the zipped down until the
+entire list has been unzipped (and so the zipped half of the zipper is empty).