8. Copy that line three times
Put Page "B" on top of Page "A". Copy that weird line onto the left side of Page B's rectangle*. Then, copy that line onto the right side of Page B's rectangle*.
Check your work. Does it look like the photo on this page?
Now, put Page "B" under Page "A". Copy that weird line from the right side of Page B's rectangle* onto the right side of the rectangle* on Page "A".
* A rectangle is easy, but any parallelogram is OK.