-This appendix tells about the mapping between MDL objects and PDP-10
-storage -- in other words, the way things look "on the inside". None
-of this information is essential to knowing how to program in MDL, but
-it does give some reasons for capabilities and restrictions that
-otherwise you have to memorize. The notation and terminology get a
-little awkward in this discussion, because we are in a twilight zone
-between the worlds of MDL objects and of bit patterns. In general the
-words and phrases appearing in diagrams refer to bit patterns not MDL
-objects. A lower-case word (like "tuple") refers to the storage
-occupied by an object of the corresponding `PRIMTYPE` (like `TUPLE`).
-
-First some terminology needs discussion. The sine qua non of any MDL
-object is a **pair** of 36-bit computer words. In general, lists
-consist of pairs chained together by pointers (addresses), and vectors
-consist of contiguous blocks of pairs. `==?` essentially tests two
-pairs to see whether they contain the same bit patterns.
+This appendix tells about the mapping between Muddle objects and
+PDP-10 storage -- in other words, the way things look "on the
+inside". None of this information is essential to knowing how to
+program in Muddle, but it does give some reasons for capabilities and
+restrictions that otherwise you have to memorize. The notation and
+terminology get a little awkward in this discussion, because we are
+in a twilight zone between the worlds of Muddle objects and of bit
+patterns. In general the words and phrases appearing in diagrams
+refer to bit patterns not Muddle objects. A lower-case word (like
+"tuple") refers to the storage occupied by an object of the
+corresponding `PRIMTYPE` (like `TUPLE`).
+
+First some terminology needs discussion. The sine qua non of any
+Muddle object is a **pair** of 36-bit computer words. In general,
+lists consist of pairs chained together by pointers (addresses), and
+vectors consist of contiguous blocks of pairs. `==?` essentially
+tests two pairs to see whether they contain the same bit patterns.