He followed the tubes for some period of time that was quite long but 
difficult to estimate. From time to time he would come to a chamber with a lamp 
and more paintings. As he crawled through the long perfectly black tunnels, he 
began to experience visual and auditory hallucinations, vague at first, just 
random noise knocking around in his neural net, but increasingly well-resolved 
and realistic. The hallucinations had a dreamlike quality in which things he'd 
actually seen recently, such as Gwen and Fiona, Dr. X, the airship, the boys 
playing fieldball, were mingled with images so alien he scarcely recognized 
them. It troubled him that his mind was taking something as dear to him as 
Fiona and blending her into a farrago of alien sights and ideas.