Index: puzzleset.doc
==================================================================
--- puzzleset.doc
+++ puzzleset.doc
@@ -18,10 +18,14 @@
 edit it using any text editor. The other three files are Hamster archives,
 and are normally written by Free Hero Mesh, so you do not need to tamper
 with the internal contents of those files by yourself. You may extract and
 insert parts of the Hamster archives if you are careful; the descriptions
 below mention what each lump means.
+
+(A "Hamster archive" consists of zero or more lumps, where each lump
+consists of a null-terminated ASCII file name, the 32-bit PDP-endian data
+size, and then the data.)
 
 
 === Class resource file ===
 
 This file contains pictures and sounds associated with the puzzle set.