Indoor adventure land: You can also buy or make tunnels and fabric tubes for your feline to run through. (bluebuffalo.com)
TUNNELS - There are two types of tunnels: open tunnels which are long, open tubes; and «chutes», which are open at one end and have a collapsed fabric tube at the other. (americanshihtzuclub.org)
An obvious example in my work would be the Nexus Architecture where fabric tubes act as a metaphor for creating a social alliance. (artspace.com)