«The tower is the result of the need to differentiate, in this case to add true value, creating the highest level of Architecture on Amsterdam’s prestigious South Axis. Truly different from the other - predominantly - glass office cathedrals, the tower is a striking presence and was quickly dubbed 'the Rock' because of the stony top that sits like a rock on the glazed base.» Erick van Egeraat

In particular, the tower can be split into three different sections; the bottom is characterized by transparency, maximising daylight and interaction with the outside; instead, the upper part curtain wall is made of natural stone and the façade has a diversity of slopes, cantilevers and recesses. In the middle, there is a mixed use of stone and glassy panels, creating lovely transitions between the two.