a:  blood vessels ~
b:  water movement cylinders
What:  
Tubes, garden hoses, highways with water, sewage pipes, water pipes, canals, rivers of cells, Erie Canal, the Panama Canal, the Suez Canal, this canal, a stream, a brook, a storm drain. In short they are kinda like any kind of circular liquid transport system.
Useful?
Writer:  Not Stated
LCC: 
Where: Reference Link Has Evaporated
Date:   Apr 30 2014  6:22 PM
# 5593 Critique Analogy
