Professor:
In my presentation on Tuesday, I said the channels behaves like a stack with first in, last out policy. In fact, the channel was design to be a queue, which is first in, first out exactly. The reason why my demostration code behaves like a stack is: the two threads in the code was in a race condition which I completely ignored. The result of thread who starts firstly produces its result after the second thread ends. 

I apologize for the mistake I have been made. IfI may, I am very happy to clarify it to the class.

Thank you!