Finished HW2

Good.  Finally got one thing done and it doesn't seems to be very stressful.

I still hope to get the HW4 and 5 last year to be finished soon.  My speed of finishing the homework largely due to the fact that I have practiced.  Should do the same for HW4 and 5 as well.

Before that, let's relax.  It doesn't hurt to have some fun some time. :)