listen-to relation
a
	b
bedeutet: a listens to b

player
	stone
	bottom
	moving-item
	standing-item
	moving-enemy
	standing-enemy

standing-stone

standing-item

moving-item
	player

moving-enemy
	player
	stone

standing-enemy

subclasses:
moving-enemy => nasobem, flying-nasobem, jumping-marchmallow
standing-enemy => needle, fire
item => bulb, slobber, tulip