On graphics browsers, the first four icons always appear, though they may be Xed out if there isn't an appropriate document in that direction. I keep the Xed icons around so that the positioning of the icons is consistent from one document to the next. If you want to go forward through several pages, you don't have to move the icon back and forth as the "Back" and "Up" icons come and go.
The "First" icon only appears if the current document has a child in my tree (as opposed to a link to someone else's documents elsewhere). Sometimes it will appear at the head of a list of sub-documents, for instance the "Things to See on the Web" list on the home page. This happens when a document is the root for a number of trees, rather than just one.
On text browsers, only those icons which are appropriate will show up. This saves you having to cursor past meaningless links. The "First" icon is usually omitted, since it genereally points to the same places as the next anchor does, and just gives you one more think you have to skip over.
Here's a picture of the setup:
Dashed lines are normal hypertext links, solid lines are icon links. The one solid one down to each group is the "First" link. Each page below the home page has an "Up" link which returns it to the section of the home page it came from. Some pages have links going forward, some back, most both. No shown are each pages link back to the beginning of the home page, and the links to the acknowledgements and credits pages (see below).
On a couple of pages, there may be extra icons tacked onto the ends of the icon lines, for various reasons (for instance, the "Tzoq" page has an icon going to the "Jean" page and vice versa). Those are generally unique to that page, and it should be fairly obvious what they do. If not, try them.
Likewise, a couple of pages don't fit cleanly into the tree structure. The Acknowledgement page is one of these: It has several "parents", and no siblings. The only icon on the page is the "Home" icon. If you want to go back to the page from which you came, and it isn't the home page, use your browsers "Back" function.
This whole icon business is an experiment of mine, to get a feel for playing with hypertext and tree-based document structures. So far, it suits me quite well -- but that doesn't mean anyone else will like it. If you have any comments, email me at:email@example.com
One last note: Entries in the "Things to See" pages which are in parentheses are ones which appear to have fallen off of the Web, or moved without leaving a forwarding address. I've left them in in case they return, but don't count on them working.