Holes were drilled through the center of both balls, the hula hoop was separated at its seam, and the Earth
ball was threaded onto the hula hoop. Because the Moon’s orbit hoop was a solid ring, the Moon ball was
sliced halfway through to the drilled hole, the ball was slipped over the hoop, and the cut faces were glued
back together. One of the ends of the hula hoop was passed through the Moon’s orbit hoop, and then the
hula hoop was rejoined, yielding interlaced hoops as shown in Figure 1.