I believe they are experimenting because they're adorably committed to methodically testing the nature of reality. Their goal, while they won't articulate it, is to verify the validity of their hypothesis: if they move forward, continuously, then they will be able to adventure around the apartment. They are, with out really knowing it, replicating their evolving hypothesizes. Above are Oscar and Felix testing their first hypothesis: if they lay very, still, then they will adventure. This hypothesis was falsified. Later they tried to adventure while each moved in an opposite direction (falsified) and then by rocking back and forth (also, falsified).