https://www.youtube.com/watch?v=mI3yiPA6npA

Generally interesting and useful, but is broadly an extended advertisement for JetPens products.

Transparent sticky notes allow one to take notes on them, but the text is still visible through the paper.

One can use separate pages to write notes and then use washi tape to tape the notes to the page in a hinge-like fashion similar to selectively interleaving one's books.