Clarify HEAD

branching/branching.tex

@@ -69,9 +69,10 @@
 \begin{frame}
   \frametitle{The current commit: \bt{HEAD}}
   \begin{itemize}
-    \item The current commit is called \bt{HEAD} (shown in blue).
-    \item \bt{HEAD} normally points to the current branch.
-    \item Or to a commit if there is no current branch.
+    \item The current commit is called \bt{HEAD} (shown in blue here).
+    \item \bt{HEAD} is actually a pointer to the current branch.
+    \item (Or to the current commit if there is no current branch -- this is
+      called detached head state.)
   \end{itemize}
   \vspace{1cm}
   \includegraphics[width=10cm]{images/head}
@@ -82,7 +83,7 @@
   \begin{itemize}
     \item Committing moves the current branch to the new commit.
     \item Of course, \bt{HEAD} moves with it.
-    \item If there is no current branch, only \bt{HEAD} moves.
+    \item (In detached head state, only \bt{HEAD} moves.)
   \end{itemize}
   \vspace{1cm}
   \includegraphics[width=10cm]{images/commit}