Here’s a clever project sent in by a designer in Italy:
"Get the pdf from the float box, and follow the instruction in it, or continue to read this post.
1) Print the pdf on an A4 paper, possibly on a borderless printer
(recycled paper is better for nature) or rescale it to a 95-98%…."
"6) Put the bookmark on the upper left or upper right angle of you book….enjoy it"
Visit his blog.