Take a straight string of finite length. Wrap the right half around the left half so that it is pointing to the right again and there is a hoop. Pass the right pointing piece through the hoop from above. Glue the two ends together to form the figure-8 knot.
Draw a sequence of pictures to illustrate the formation of the figure-8 knot.
Explain why it is possible to have a picture of a figure-8 knot with 100 crossings.