Getting Started

If you are building a house, things like walls, doors, windows, cabinets, and lights will form part of your vocabulary. None of these things stands alone, however. Walls connect to other walls. Doors and windows are placed in walls to form openings for people and for light. Cabinets and lights are physically attached to walls and ceilings. You group walls, doors, windows, cabinets, and lights together to form higher-level things, such as rooms.

Not only will you find structural relationships among these things, you'll find other kinds of relationships, as well. For example, your house certainly has windows, but there are probably many kinds of windows. You might have large bay windows that don't open, as well as small kitchen windows that do. Some of your windows might open up and down; others, like patio windows, will slide left and right. Some windows have a single pane of glass; others have double. No matter their differences, there is some essential "window-ness" about each of them: Each is an opening in a wall, and each is designed to let in light, air, and sometimes, people.