3.1.2. Rotor

Buildings of this type have the same cross section for their full height. An example can be a rectangular or cylindrical solid (Figure 2a). Within this group the following modifications may exist:


**Figure 2.** Rotor type of high-rise buildings: (**a**) Mode Gakuen Cocoon Tower (Tokyo, tube system with concrete columns), (**b**) Swiss Re (London, diagrid frame tube system), (**c**) Westhafen Tower (Frankfurt, diagrid frame tube system), (**d**) Torre Agbar (Barcelona, diagrid frame tube system) and (**e**) Tornado Tower (Doha, concrete core system with an external tubular steel diagrid), figure by authors.
