Faun and Games by Piers Anthony

pictures couldn't provide that.
     
    Or could they?   Maybe it was worth a try.
     
    "Dot, just how detailed can your pictures be?"
     
    "Infinitely detailed," she said proudly.   "I can make dots so small they
    can't even be seen individually."
     
    "Then let's make a special picture.   Of a manual.   On the cover it says
    I,OCOMOTIVE OPERATING INSTRUCTIONS.   Can you do that?"
     
    "Sure.   But that doesn't require much detail." The picture appeared in
    the window, a book with the required words.
     
    "Very good.   Now can you open it?"
     
    The cover turned, in much the manner of another door opening, revealing
    the title page inside.
     
    "Show the contents page."
     
    Another page turned, and CONTENTS showed.
     
    Forrest leaned across to read it.   Near the bottom of the page was a
    listing for Chapter 10: STOPPING.   "Turn to page fifty," he said,
    reading the indicated page number.
     
    The pages flipped across, stopping at 50.   But the print was too small
    to read.   "Can you make the page larger?"
     
    The image expanded, until it filled the whole window, and the print was
    legible.   Forrest read it avidly: TO STOP LOCOMOTIVE IN ITS TRACKS, PULL
    THE CORD ABOVE THE SEAT.
     
    He looked up.   There was the cord, that he hadn't noticed before. He
    reached up and pulled it.
     
    There was a squeal as the train hurtled to a stop.   Seat belts jumped
    out to clasp the two of them, as well as all the dummies in the rest of
    the coach.   oops-he had forgotten that detail.
     
    "You did it!" Dot cried.   "You stopped the train!"
     
    "Can you show the contents page again?"
     
    The pages turned back.   He found the chapter for SEAT BELTS, and turned
    to that page: TO RELEASE SEAT BELT, PUSH BUTTON THEREON.
     
    Sure enough, there was a button.   He pushed it, and the belt unclasped
    him and disappeared on either side.   Dot did the same.   "You figured it
    out," she said, pleased.
     
    "Let's get off this crazy train before it starts again," he said,
    standing.
     
    But she shook her head.   "Thanks, no.   This is your Challenge, not mine.
    My job is on this train of thought."
     
    He had suspected as much.   "Thanks for your help, anyway."
     
    "It was a pleasure.   You're a nice person."
     
    He walked along the aisle to the end of the coach, where the door had
    folded down into steps.   He stepped down and off.   As soon as he did,
    the steps folded up again, sealing the train, and it started moving
    again.
     
    "Well, I guess you got through that one," D.   Sire said, fading into
    view.
     
    "You can go any time, demoness."
     
    He waited while the train rolled out of the way.   Beyond the tracks was
    an open door in the wall just like the one Dot had pictured.   He crossed
    the tracks and put out a cautious hand, just in case the doorway wasn't
    real.   His hand didn't bang.   He stepped through.   He had won the second
    Challenge.
     
    Suddenly he was horribly frightened.   He reeled, staggering back through
    the door.   His fear abated.

 
    What had happened?   He hadn't seen any monster or hurtling 10comotive or
    anything; why had he been so suddenly and awfully afraid?
     
    "I think you have a problem, faun." Sire faded out, satisfied.
     
    He stepped forward again-and was blasted by the fear.   He reeled back
    again, out the doorway.   It was this place: he was afraid to enter it.
    But he had to enter it, because it was the only entrance to the castle
    he had found.
     
    He stepped close to the entrance, stopping just short of the fear, and
    peered in.   There was a small man, or maybe an elf, or maybe in between.
    "What's this?" he asked.
     
    "Isn't it obvious?   I am LA, the lost angel.   I am here to help you
    enter the castle.   But first you must conquer your foolish fear."
     
    So it was the third Challenge.   All he had to do was nerve himself and
    go on through.   It seemed simple enough.   After all, LA didn't seem to
    be afraid, so probably there was nothing