This function has four parameters: "subject", "velocity", "gravity" and "front". The "subject" parameter is the object that will be thrown. The "velocity" parameter is the velocity the object has when thrown. If you set the velocity to 0, the object will just fall. If you set the velocity to 10, the object will be throw up and then fall. The "gravity" parameter is, literally, the gravity. It increases the velocity of the object, so the big is the value of the gravity, the faster the object will fall. The "front" parameter is like the horizontal velocity that the object have when thrown. If you set "front" to 0, the object will fall down. If you set the "front" to 3, the object will go a little forward.