trashing the world

for their birthday, which was thanksgiving, i made the boys a collage on the playroom wall out of old national geographic pictures. the bottom is sea life then it goes up to land and land animals, then the sky and finally starts and space at the top. in the top left corner was a picture of the earth from outerspace. a few days ago silas ripped off the picture of earth, crumpled it up, called it trash, and then proceeded to take it to the kitchen to throw it away. i am not certain how to interpret this action. is it possible for a 2 year old to be ironic?