Weekly Theme: Week of October 9-15, 2016

The Theme for this Week is Circulation.  So what does it mean to circulate?  One meaning is, simply motion, such as "the circulation of blood in the body".  But also, Google mentions "the public availability or knowledge of something", and includes the example, "his music has achieved wide circulation".  I'll simply bring up a slight variation, the "circulation of ideas", and leave it at that.  Thanks!