The first page opens left to right, revealing this:
Another left to right opening, which has a little carry-over from the previous window, and then opens to our last window at the back of the card.
This is the fourth and final window, when you open it top to bottom, it brings you right back to the beginning, allowing you to keep on going!
You could place photos within the card as well, or little notes, messages or whatever works for you! The biggest note is you'll want to keep each window as flat as possible since it all folds within itself.
Visit my website to download the instructions to create your own neverending card!