Two pages at tier 3 (Pictorials 2&3) are children of parent page, TEXT 2-X, at tier 2. If you have accessed one of these pages at tier
3, you can move along the tier from PICTORIAL 2 to 3 and back to 2, but the other pictorials are inaccessible, if using only the BACK or NEXT buttons at the end of each page. If at Pictorial 2 or 3, a click on
the UP button take the reader to the respective parent page (TEXT 2-X). If at tier 2, a click on the UP button takes the reader HOME. At HOME, where there is only one chapter, the BACK, NEXT, and the UP buttons are
inoperative (there are no options at level 1 when attempting to use these buttons.