Simpsons
Metaphors 

Historians are not sure who Lao Tzu was.  It is possible that he was Confucius' instructor but this is inconsistent with other documents.  The time period in which he lived is debatable.  It is believed the Lao Tzu is a nickname or a title.  This nickname could mean "old man" or "master".
This was found in http://www.massart.edu/community/GALEBN/LaoTzu.html


Thirty Spokes
The whole poem is a metaphor.  He uses a wheel, a vessel, and a house to illustrate how people misinterpret what is useful and what is not.
Man of Highest Power
We found three metaphors in this poem.  The first is,"Now ritual is the mere husk of loyalty and promise-keeping".  This metaphor symbolizes a husk of corn.  The outside of the husk symbolizes loyalty and the inside symbolizes promise-keeping.  The second metaphor is,"Foreknowledge may be the 'flower of doctrine'".  An example of this would be an apple tree, the apples on the tree are what is important, not the flower.  The third metaphor is,"Therefore the full-grown man takes his stand upon the solid substance and not upon the mere husk".  This means that man knows what is most important, priorities are in order.


The two poems symbolize the importance that humans place on superficial things and lose sight of what is most important.