Page 3 of comments at Those balls

Sorry to be a human paraquat... But Jumping into that would likely hurt like a bitch. That is, after your weight has pushed all the balls aside and you slap the plastic lined linoleum floor! Little balls work because they push against each other at a rate that allows friction to dominate the displacement of your body, they also have a flexible netting holding them in (which expands with more objects introduced to the area).