What Is the UML, and Why Is It Important?

Let us begin with a simple example. If I write on the whiteboard:

1 + 1 =

anywhere in the world, people understand what I am trying to say. In fact, at this point, someone in the audience always volunteers "2!" When that happens, I complete the equation:

1 + 1 = 2

and explain that not only are we understood around the world, but also we usually get the right answer, too.

This is a good example of a universal notationthat is, the number system. People all over the world use it to communicate with each other. An English speaker can write it down, and a person speaking Mandarin in China can understand it.

Although this example seems trivial at first sight, it really does reveal an amazing fact: Numbers are universal, and certain symbols such as + and = have the same meaning all over the world.

The other really nice thing about this example is that anyone who has a first-grade education can understand and appreciate it. It has the unfortunate disadvantage of appearing to be more trivial than it really is.