insert demo screenshots

Author: yichenghuang980

README.md

@@ -2,20 +2,25 @@
 ## Project 1
 1. Calculate Amortization, APR(annual percentage rate)
 2. Format them in a nicer and readable way
+![interest](https://github.com/yichenghuang980/OO_Programming_Python/blob/master/screenshots/pj1.png)
 
 ## Project 2
 ### Rules
 1. Initialize a 10x10 gridlines and randomly generate barrier in the path of the moving object.
 2. The object will move one grid to the direction that the user clicks(namely, right, left, up, down).
 3. Each time the object moves past a grid, the score will be updated with +1. Each time the object moves past a barrier, the score will be updated with +5.
 ### General
+![gameStart](https://github.com/yichenghuang980/OO_Programming_Python/blob/master/screenshots/pj2_start.png)
+
 1. Display a panel containing previous top 4 scores, player names, and different functional buttons.
 2. Display corresponding contents as the user clicks different buttons. If the user wants to play, it will display grids(game panels) where user can click to move the object.
 3. When the object hits the target area, the program will calculate the score and display it in the beginning panel if it beats one of the existing top 4 scores.
 4. Get the top 4 game player's names and their scores after they move the object to a target area.
 5. Update the panel containing top 4 scores, player names, and different functional buttons.
 
 ## Project 3:
+![gameMiddle](https://github.com/yichenghuang980/OO_Programming_Python/blob/master/screenshots/pj2_play.png)
+
 ### Improvements
 1. Add diagonal movement function on the basis of project 2.
 2. Sleep for a given time period defined by user.