I have been fascinated by this painting for as long as I can remember.  As a child I would stare at it often, mesmerized by the colors and patterns.  One part that always jumped out at me is an object or figure done in dark markings, just below the graduated cylinder in the lower middle.  I always saw it as a small robotic stick figure strolling through the lab scene.  But it could just be more laboratory apparatus.  What do you see?

What appears to be a representation of electric or computer circuits with floating reflective elements and glowing dots.

Dad was always fascinated with the merging of art, science, and mathematics, so naturally DaVinci became a subject of one of his art pieces.  The math/science motivation is why this artwork is assigned to the science category.