These are notes and pen-over-chalk sketches of a 4-month-old fetus (and the structure of the placenta) as seen by Leonardo da Vinci. The first idea of the fetal position came from this notebook. I’m working hard not to think about how Leonardo came to draw this picture.
The photograph of the notebook was taken by Luc Viatour, who has many other marvelous scientific images in his portfolio (as well as gorgeous pictures of European architecture and beautiful Belgians).
Happy New Year.