-- File model.vhd. Encapsulates Ball entity.
-- s - position, v - speed, a - acceleration

ENTITY Model IS
  PORT ( QUANTITY start, ground : IN REAL_VECTOR(3);
         QUANTITY s, v, a       :OUT REAL_VECTOR(3) );
END ENTITY Model; 

ARCHITECTURE First OF Model IS 
BEGIN 
  MyBall: ENTITY Ball(Simple)
          PORT MAP ( start, ground, s, v, a );
END ARCHITECTURE First;