The recessed edges that intersect near the page buttons are called the back pages. The default notebook's back pages intersect in the bottom-right corner, which means the recessed pages are on the bottom and right edges. This setting is specified by the BKS_BACKPAGESBR style bit. The back pages are important because their intersection determines where the major tabs can be placed, which in turn determines the placement of the binding and the minor tabs.
The following table describes the available notebook control styles for a old notebook:
┌──────────────────────┬─────────────────┬─────────────┬────────┐ │Back Pages │Major Tabs │Minor Tabs │Binding │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Bottom-right (default)│Bottom │Right │Top │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Bottom-right (default)│Right (default) │Bottom │Left │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Bottom-left │Bottom (default) │Left │Top │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Bottom-left │Left │Bottom │Right │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Top-right │Top (default) │Right │Bottom │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Top-right │Right │Top │Left │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Top-left │Top │Left │Bottom │ ├──────────────────────┼─────────────────┼─────────────┼────────┤ │Top-left │Left (default) │Top │Right │ └──────────────────────┴─────────────────┴─────────────┴────────┘