"We have to go," Nell said finally, and Carl arose and followed her 
through a randomly chosen exit. The tunnel forked and forked again, and Nell 
chose forks by intuition. Sometimes the tunnels would widen into great caverns 
full of luminescent Drummers, sleeping or fucking or simply pounding on the 
walls. The caverns always had many outlets, which forked and forked and 
converged upon other caverns, the web of tunnels so vast and complicated that 
it seemed to fill the entire ocean, like neural bodies with their dendrites 
knitting and ramifying to occupy the whole volume of the skull.