There are also different models that the Abos use. Some are non-symetrical, i.e. one leg is longer than the other.
Some S.W. American Indian tribes used similar weapons, simply called "Throwing Sticks" and used them mainly for hunting rabbits. Our Indians never figured out the "return to where thrown" concept that the outback Abos did

...a very interesting design using two airfoils with each leg the REVERSE profile of the other.