Example:
<PRE>        <IMG SRC="Lecture10Fig4.gif"></PRE>

<P>Insert 17
<PRE>        <IMG SRC="Lecture10Fig5.gif"></PRE>

<P>Insert 6. Split: Left=[2,3], Middle=5, Right=[6,7]
<PRE>        <IMG SRC="Lecture10Fig6.gif"></PRE>