Png files

![plot1](https://cloud.githubusercontent.com/assets/8470167/4966737/1d0764c6-67e0-11e4-870b-1d37451ecbe3.png)
![plot2](https://cloud.githubusercontent.com/assets/8470167/4966739/2971c3be-67e0-11e4-96cb-7b7ec281bce9.png)
![plot3](https://cloud.githubusercontent.com/assets/8470167/4966740/29857846-67e0-11e4-9160-8b2527adbce8.png)
![plot4](https://cloud.githubusercontent.com/assets/8470167/4966741/29a9a644-67e0-11e4-8e67-709147bf80ea.png)