He lost me at > Well, if we neglect the translation part (the bottom row), then the pure rotation part simply describes the new location of the points on the c

He lost me at > Well, if we neglect the translation part (the bottom row), then the pure rotation part simply describes the new location of the points on the cube: Even though im very good at visual with say complex graphs. I really didn’t get where the ‘simply’ part really comes from..