A disused smoke stack in the town of Kassel, more or less at the very heart of Germany, has undergone a peculiar transformation. Glance up at the tower and the you will be met by the disarming sight of alternating floating and missing sections of chimney stack, courtesy of a bold intervention, named Sky Stack, by asdfg Architekten.

Apparently fixated by the existential worth of obsolete industrial architecture and infrastructure, asdfg (try typing that on a qwerty keyboard) has, through this modification, attempted to prompt the same wondering in others.

Close up, it's clear that this is a simple trick. There are no cameras, no screens; instead, they do it with mirrors. More accurately, five flexible reflective strips have been wrapped around the chimney, creating the impression, especially at a distance, that the stack is broken by the sky.

Judging by the photography, from the right vantage point with the right conditions, the effect is really rather striking.

Sources: asdfg, Architizer