At least it looked like black rubber, with sort of floppy edges. They obviously had the plumbing working, but he wondered what they'd say if you asked to make your own contribution to the Grotto? On his way here he'd noticed that one of the bars was topped with a slab of something murky green and translucent, lit from below, and he'd hoped they hadn't made that from what they'd sawn out of the stairwell.