These two 56- and 50-storey towers feature elliptical-shaped slabs that are twisted around a central vertical axis resulting in a curvaceous shape that has prompted the Marilyn Monroe nickname. The rotating slabs presented two key structural challenges. The rotation of every floor meant that the engineers had to calculate the maximum load on every structural element. To address the thermal transfer between the open balconies and the interior, a new kind of thermal break was devised where the balconies meet the wall in two-foot segments alternating with four-foot gaps.