Ideas are Viruses

Description of motion:  One hand extends forward, palm facing the floor and moves in a circular motion as if spreading a substance.
Observed:  At dinner.  4 people seated around a table.
Example:  "I'm putting a lot of work into this.  I really hope this idea will spread."
Link to use:  ONE Thing: A Mission to Spread Hope, Peace, Joy and Love
Use:  Used to describe the replication of an idea moving through a large group of people.
Metaphor: Ideas are Viruses
Explanation:  You can think about the action of spreading in a number of ways.  You can think about it as a virus spreading through a population.   You can think about it as a knife spreading jelly on toast, or you can think about it as spreading a beach towel on a sandy beach.  The act of spreading in all three examples is in relation to the growing surface area that is covered (beach towels, jelly, viruses).  

Viruses are a much less visible example of this kind of spreading, and are not so apparently related to surface area.  However, if you think about the visual representations that we usually use in relation to viruses, such as the map above, you can see that they usually exist in 2 dimensions.  Because of this 2 dimensional view, a virus increases its surface area as it spreads.  We talk about viruses this way, because we are thinking about them in this 2 dimensional map like way.  

Like viruses, ideas are also invisible to the eye and they also replicate themselves through populations of people.  The above maps show the spread of Buddhism, Democracy and Jazz.  These ideas are also pictured in flat 2-D maps, where the ideas are either a growing mass of color or a series of directional arrows showing the movement of its growth.  Since we understand the growth of ideas in 2 dimensions as well, we also talk about it as the spreading of surface area.