The 4 sections change. Something to do with Pitch, Yaw and Roll, if I remember one of Annikans earlier posts correctly.
The spinal column is rotating in a diagonal or oblique plane which is a combination of those great pics!.
I think from down the line view many like to draw a straight line to represent the spine and its angle. And I think, no real knowledge that although that is nice and maintaining the angle from down the line seems to make sense to me, the spine is not a straight line and in order to accomodate rotation and shifting, parts must be in motion.
The way I understand this is... there ideally is little, if any change in the angle of the TORSO when one is bent over the ball, and throughout the Stroke. There is no BOB or SWAY. The different parts of the SPINE(cervical, thoracic, lumbar, sacral)however, DO CHANGE during a swing.
Tiger Woods, and Adam Scott would be obvious examples of this. Their cervical and thoracic angles obviously change from their Address angles, but the overall TORSO angles are very much the same as at Address.