In Open Frameworks

1. Create a class named "WaterDrop" in header file and source file format in your OF project.

2. Your 'WaterDrop' class will define how to draw one water drop, and how the water drop moves. Each water drop is required to have simple gravity effect.

3. In the 'ofApp' class of your OF project, use the vector container to store a bunch of pointers of objects of your 'WaterDrop' class. Each element (WaterDrop object) of the array will have different random location (x and y coordinates), different random size. Each WaterDrop object is allocated at runtime (dynamic allocation)

4. Make a continue (The rain never stop) raining effect.

5. Add Start Screen to let the user choose a small rain, medium rain, or heavy rain your program should be able to return to the Start Screen to change how heavy the raining would be.