Update my answer to Exercise 3.23.

This is a major update. I have modified the following 2 file heavily:

	Exercise_3.23.pdf
	Exercise_3.23.tm

Additionally, implementation of this exercise have been included:

	Exercise_3.23.scm
	Test_of_Exercise_3.23.scm

Thank you!
							Lawrence X. Amlord
							  Sept 29th, 2013
							  Xi'an, China