Comfortable book page holder (parametric)

Parametric book page holder with elevated thumb rest and customizable text option. Verision 2 (bookthing-05): Thumb rest elevated to 5mm above horizontal axis Added font options Removed rounded cap on the nadir/valley point. (I didn't like the shape of it.) Customizer will now default to thumb_rest_delta = 5 Problems with other book page holders: Thumb pinching the spine of the book = hand cramp after a short while. Thumb position is too close to the book: Requires uncomfortable "pinch" hold. Forces thumb to be parallel to book spine: Not ergonomic. Narrow: May spin out of position unless held very tightly. Most book page holders have the thumb/finger part close to the level of the book opening (valley?). I find this position uncomfortable since it forces you to pinch the spine of the book. Also, holding the book with the thumb parallel to the spine of the book is not exactly ergonomic, since most of us don't have arms that grow out from the center of our chest. Many are also somewhat