This kind of book mark does not fall off than other kinds. It holds on to ur page. For example on the pictures.
This part use origami paper.
Step 1: Fold to triangle
Always start at the back. OK then fold it to a triangle
Step 2: Fold
follow the pics below
Step 3: Fold and unfold
the middle part fold it in half down
Step 4: Final step
On the left and right part that look like a triangle put them up to be like a square.
Follow the pics.