rule based

A rule

1. Position a triangle
2. take another triangle
   place it on top of the previous one
   wist it by an angle (W)
3. take another triangle
   place it on the position of the penultimate one
   twist it in the opposite direction by the angle (-W)
4. take another triangle
   place it on the position of the penultimate one
   twist it by the angle (W)
5. repeat 3
6. repeat 4
7. and so on until you run out of triangles.
   

Union body

unites the two sets

a ruled body

Take a closed space curve
mark an even number of points roughly evenly on the curve.
connect any 2 points together
choose 2 neighboring points and connect them
you get a ruled surface.