On the left it is in the contracted state.
Notice that 4 spheres are formed, (+)(-)(+)(-)
On the right it is expanded. You can see that this is a form of nesting but it is limited to one 'nest' per unit cell.
To to get the pattern you can print to assemble your own, Click Here
Here a circle is defined that is an axis about which the whole affair can rotate much like a smokering.
The small object in the middle is a single unit cell turned back on itself to form a 6 element object which is not mobius. That means that if cut in half parallel to the edges it will fall apart into 2 seperate loops of a triangle form.
To to get the pattern you can print to assemble your own, Click Here
Return to Phase 3