Foto: "<a href="https://ccnull.de/foto/view-down-the-hollow-in-floors-for-parametric-cone-construction-in-my-zeil-shopping-mall/1019089" target="_blank">View down the hollow in floors for parametric cone construction in My Zeil shopping mall</a>" von <a href="https://ccnull.de/fotograf/marco-verch" target="_blank">Marco Verch</a> via <a href="https://ccnull.de" target="_blank">ccnull.de</a> - <a href="https://www.flickr.com/photos/30478819@N08/50392334538/" target="_blank">Bildquelle</a>, <a href="https://creativecommons.org/licenses/by/2.0/de/" target="_blank">CC-BY 2.0</a>