??ANSWER TO EXERCISE 11
Object -> glass_box "glass box with a lid"
  with name "glass" "box" "with" "lid"
  has  container transparent openable open;
Object -> steel_box "steel box with a lid"
  with name "steel" "box" "with" "lid"
  has  container openable open;

Back to the exercise in section 11
Mechanically translated to HTML from third edition as revised 16 May 1997. Copyright © Graham Nelson 1993, 1994, 1995, 1996, 1997: all rights reserved.