Titian, Venus of Urbino, 1534 (page 454) - How do the orthogonal lines relate to this piece AND as described in the video?

Link 1: https://www.khanacademy.org/humanities/renaissance-reformation/early-renaissance1/beginners-renaissance-florence/v/linear-perspective-brunelleschi-s-experiement

Link 2: https://www.khanacademy.org/humanities/renaissance-reformation/early-renaissance1/beginners-renaissance-florence/v/how-one-point-linear-perspective-works