The block, that is intersected by a canal, consists of three different buildings, each with a hybrid form. Each hybrid contains high-rise apartments (eight storeys) and low-rise homes (three-storeys), with a smooth transition between the two types. Each hybrid owes its characteristic form to the silhouette of the high-rise block.
Block 23B1 has 26 low-rise homes and 52 high-rise apartments, a commercial area, and a semi-sunken underground car park.
The precisely stipulated building envelope, in combination with the programme, requires a double line of buildings on top of the ground area. An inner street has been cut out of the mass for this purpose. This inner street intersects the block in different ways and leads to a diversity of types of homes and apartments. With respect to the low-rise homes, it runs between two rows, one on either side of the street, which are orientated towards the outside or inside of the block. As for the high-rise apartments, the street changes form depending on level: at ground level it is a roofed inner street in two and three layers that gives access to maisonettes. Between the second and the fifth storeys it is a corridor leading to apartments. The apartments on the sixth floor are accessed from an open inner street again: a rooftop street flanked by detached and semi-detached housing units in two storeys. A double system of stairs winds its way through the streets and links all the floors together.