Bicycle frame just came because I need a way to be able to hold and rotate the
cylinder. That was my initial thought as the cylinder was hollow.
It's just coincidence. If he's trying to use a obvious linear step to problem solving,
evolving, he is an opportunist. I then remembered my ring chainsaw idea surrounding a tree.
I changed the saw into gears. From the outside. Keeping the cylinder hollow, to connect/build
pillars within. To eventually rotate again to remove the outer metal cylinders.
(As metal is expensive) If the inner frame, like a bicycle, stays there,
it gets in the way of stacking the pillars from within. Further, this is another
variation of the idea Mr Musk and Mr Bezos is using. Stacking sliced cylinders
on top of each other to create rockets. It's as simple as that.