thank you Armando, Seapy and timh for looking and commenting
mostly these crane masts were mounted by an auto crane and then their boom is done by themthelves...but I am no crane specialist, I am working on and with soil
...like the idea of cloud based crane...
in the first pic you might think I added 2 images, but it was the same printed poster, built as a cube wall at the exhibition around the real crane as in the 2nd one,
where it is more clear by the guy and the shelf, beeing hardly in the clouds