Turning the example on the previous page - with hard planes immediately adjacent to the beads is tricky. The bead is easy. Getting the straight planes ain't.
But you'll find that turning a half cove on either side of each bead is easier to do - and provides a smoother transition between adjacent beads.
Stu's Dungeon has a great page "Turning Demonstration by Jean Francious Escoulen" of a 3 Centers Multi Axis turning.
Click Here to get to that page.