john black stone tells us about a newark tect in the bay area. >> reporter: the sounds of everyday lifeng more than background noise to most people. >> as i move around, i can hear how the space changes. >> reporter: for chris dough knee, they're clue -- downey, they're clues and markers to where he is and where he's going. >> i knew that was the kitchen. >> reporter: chris' world has been in total darkness for three years. he thought he was just getting odor is having trouble -- older and having trouble focusing. >> i couldn't see the ball anymore coming at me. >> reporter: they successfully removed the tumor but in the process he lost his sight. and his work depended on sight. chris is an architect. but he couldn't imagine giving that up. >> well, what else would i do? i could always -- the other thing i'd like to do is a tour guide. that seemed to be somewhat out of the realm of pocket possibility right now. >> reporter: in your mind, you can still see. >> oh, yeah. the creative process was intact. what i needed was new tools. >> reporter: embossed building plans, is braille blueprin