Automotive
If you walk up to it, it might seem to be some abstract nonsense, but if you look down a row of them:
For some other interesting bike racks: http://justacarguy.blogspot.com/search/label/bike%20rack
https://sunpig.com/martin/2004/11/07/unemotional-design-the-new-scottish-parliament-building-at-holyrood/
http://www.materiaincognita.com.br/ilusao-de-otica-transforma-todo-o-bicicletario-numa-unica-bike/