i got my hands on a script but i dont get this bit can anyone help?

code:ph_setgravity (vector(0, 0, -386)); // set the gravity
phent_settype (ball, PH_RIGID, PH_SPHERE); // set the physics entity type
phent_setmass (ball, 3, PH_SPHERE); // and its mass
phent_setfriction (ball, 80); // set the friction
phent_setdamping (ball, 40, 40); // set the damping
phent_setelasticity (ball, 50, 20); // set the elasticity
while (1)
{
ball_speed.x = 25 * (key_cur - key_cul); // move the ball using the cursor keys
ball_speed.y = 25 * (key_cuu - key_cud); // 25 sets the x / y movement speeds
ball_speed.z = 0; // no need to move on the vertical axis
phent_addtorqueglobal (ball, ball_speed); // add a torque (an angular force) to the ball
camera.x = ball.x - 300; // keep the camera 300 quants behind the ball
camera.y = ball.y; // using the same y with the ball
camera.z = 1000; // and place it at z = 1000 quants
camera.tilt = -60; // make it look downwards
wait (1);