The player has an container empty box in which he can add dynamic boxes clicking inside it with the mouse. After that the player can shake the container and make the boxes inside move. Every time the boxes collide with each other or against the walls of the maracas a sound is played.
You are playing a Maracas!
I used Box2D library for physics simulation and OpenAL for loading and playing sounds.
NB: having this working code, the next step of the project is to make it an app and port it on mobile devices such as smartphones or tablets with android