[texhax] problem with \mark, or with me?

[Stan]

After having difficulty creating some macros involving \mark, I returned  
to the basics and set up the situation described on page 258 of the  
TeXbook, and typeset it using Plain TeX.  Unfortunately, my results don't  
match those described in the book.  Everything in the file I produced is  
shifted by a page, so for example, the state of \topmark etc. that the  
TeXbook says should be on page 3, I have on page 4.  Is this just some  
careless mistake on my part?  Here is the text from my file:


first page

-\topmark-
-\firstmark-
-\botmark-

\vfill\eject

second page

mark a\mark{$\alpha$}

-\topmark-
-\firstmark-
-\botmark-

\vfill\eject

third page

-\topmark-
-\firstmark-
-\botmark-

\vfill\eject

fourth page

mark b\mark{$\beta$}

mark c\mark{$\gamma$}

-\topmark-
-\firstmark-
-\botmark-

\vfill\eject

fifth page

mark d\mark{$\delta$}

-\topmark-
-\firstmark-
-\botmark-

\vfill\eject

sixth page

-\topmark-
-\firstmark-
-\botmark-

\vfill\eject

seventh page

-\topmark-
-\firstmark-
-\botmark-

\bye