Angry Birds is one of the most popular mobile games based
on physics [1]. The goal in the game is to shoot a bird using
a slingshot and thus damage pigs. Because the targets often
remain inside a building structure, it is difcult to directly
kill the pigs. Instead, the game requires a type of strategy
that destroys parts of the buildings and indirectly damages the
pigs. In this way, it is possible to clear a stage using a limited
number of birds. Because the game is based on physics,
the player needs to consider relationships among objects,
building structure, and the properties of objects. Fig. 1 shows
a screenshot of the mobile game.