**A rule**

- Position a triangle
- take another triangle

place it on top of the previous one

wist it by an angle (W) - take another triangle

place it on the position of the penultimate one

twist it in the opposite direction by the angle (-W) - take another triangle

place it on the position of the penultimate one

twist it by the angle (W) - repeat 3
- repeat 4
- and so on until you run out of triangles.

**or**

Use triangles instead

Cork coasters.

**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.

The link to **Karl Schlamminger **must not be missing

https://www.karlschlamminger.de/skulpturen