Abstraction Analogies

     I recently "attended" the webinar "Cooperative strategies" with guest speakers...Jeff Gray, Ruth Farmary, Blake Cook and Rebekah Lang I learned so many strategies I was able to take straight into the classroom. It was great to have an activity easy to implement and which renewed our energy as the school year nears an end.  I used the debate carousel, which everyone enjoyed. 
    You can watch the video of the webinar here.  The slides from the presentation can be viewed here.
One of the gems from the webinar was also a tangent from the theme. Blake Cook gave an example of how he uses a cooperative strategy on the lesson of abstraction. He described his lesson, saying he starts with a close up of a Van Gogh painting and then pulls back so the whole painting can be seen as a metaphor for abstraction. Nicole Reitz-Larson, the moderator,  chimed in saying that she uses the analogy of a toilet for abstraction.  "You don't need to know how each part works, but you do want the whole thing to work!" 
    What is your favorite abstraction analogy to use in the classroom?