Spotheim: Well, think about an ice-skater spinning a pirouette on one skate. When he wants to slow down, what does he do? He drops the other skate to the ice and controls the spin, turning more slowly until he stops. But it doesn't mean that he couldn't continue turning. He would just lift the other skate back off the ice, you see? That is the basic idea of how the two pivots work.
Scull: They have to be close to each other?
Spotheim: Yes, so the second pivot doesn't hinder the travel of the main pivot. You must understand…