It's not quite visible from here
Collaboration with Nuno Rodrigues de Sousa
A window on the north side of a garret room gives onto a wall, part of a pediment that tops the building’s main façade. In the space between window and wall a periscope was built out of PVC tubing, with two circular mirrors fixed to it with metal screws. The periscope is attached to a structure of wood and MDF. This instrument makes it possible for someone who is at the window to see a part of the square the building gives onto, part of the street on the east side of the square and the tops of the surrounding buildings.
There are two mirrors inside the periscope, on opposite extremities of it, positioned parallel to one another. The reflected image is slightly distorted due to an optical anomaly in one of the mirrors, but apart from this it is perfectly visible. The periscope can be rotated by 360º horizontally and 40º vertically. When the upper mirror is turned south an inverted section of the building roof can be seen. No part of the Tagus river is visible from this position.