Example: Defining Spawn point of different behavior
<SpawnBacchus          x="50" y="50" number="4">
    <Alternative version="0.2.8">
        <SpawnArthemis x="50" y="50" xdir=" 1" ydir=" 0" />
        <SpawnArthemis x="50" y="50" xdir="-1" ydir=" 0" />
        <SpawnArthemis x="50" y="50" xdir=" 0" ydir="-1" />
        <SpawnArthemis x="50" y="50" xdir=" 0" ydir=" 1" />
    </Alternative>
</SpawnBacchus>
As Arthemis would have known about Spawn, it is better to declare
it as SpawnBacchus. Thus Bacchus can operate on it using the new
behavior, and Arthemis can use the older declaration of Spawn.
Nota: This new syntax is artificial and not planned.