Starting with B_dip, you can place a bar magnet on the carousel and let it turn in a circle
B_orb: same reasoning as previous one, but now you replace the magnet with the electrically charged ball
B_fermi: We are going to use the fact that the child can’t sit still due to eating too much sugar from the foodstand on the fair where the carousal is also present. I am not sure if it is the magnet or the ball that is important in B_fermi, so I am just going to give the child both things and put him on the carousel. Due to little Johnny’s abundance of energy, he will start running around and sometimes be at the center of the carousel.