Introduction

A metaphor uses analogy to make it possible/easier to share a vision of some relevant subject that may not be easily comprehensible bye everybody involved.

From "What is Extreme Programming":

"Extreme Programming teams develop a common vision of how the program works, which we call the “metaphor”. At its best, the metaphor is a simple evocative description of how the program works, such as “this program works like a hive of bees, going out for pollen and bringing it back to the hive” as a description for an agent-based information retrieval system."

Discussion

Let's everybody here comment with suggestion's for a metaphor or a small set of them, to help us go ahead.