Rotation Tower
A simple square of four upright Bioblos makes up the horizontal section.
Each of the next layers is placed rotated by 45°.
TIP: If you use a pentagon or hexagon instead of a square, beautiful cylindrical towers with high stability result. Take a look, for example, at the colourful, high tower at the very back of our Bioblo panorama (click on the picture for the high-resolution version):