Oh, my... this is so cute (and tiny)! A new size faux book to put together with a wrap-around cover and a box area inside for hiding a trinket building a little shrine.
The finished size is 1-5/8" wide x 2-1/4" tall (the inside box is 33mm wide x 47mm tall x 17mm deep).
Just finish with a strip (or 2) of washi (or linen) tape on the spine. And leave yourself room for the cover to close.