https://docs.google.com/a/wostudent.net/presentation/d/15VKQiIF88UrCiuwJicm3gKT1pusnP4-DFegARwRMR9M/edit#slide=id.p

1. http://youtu.be/4mqV_OXTIt4

2. http://youtu.be/aKduNgfePLU

3. http://www.youtube.com/watch?v=4aK76DoxKGk

4.