A simple loop has two sides. You can’t get
from the red side to the green side without crossing the edge. If you cut the loop, twist
one end by 180 degrees, or π radians, and connect them again, you will have a Möbius
strip: a mathematically non-orientable surface with only one boundary. Now, you can travel along the red side to
the green without going over the edge. If you twist the end again for a total of
360 degrees, or 2π radians, you will have a twisted loop. You again can’t get from the red side to the
green side. If you twist the end a third time for a total
of 540 degrees, or 3π radians, you will again have a Möbius strip. Our demonstration is a 3π Möbius strip track.
By the time the superconductor has gone around the loop once, it has rotated 540 degrees
about its own axis. This animation shows you how to twist a loop
540 degrees to get a 3π Möbius strip track.