Each time one knot
from the left and the next from the right give you a flat result, keep
working from one side and it will spiral.
If you run out of outside strands let the inner stands jump and take over.
A key fob or zipper holder can be made by folding your string like this and
tying with the outer strands. Have a friend hold the top of the strands in
your first try.
A fob in 2 colors is made with 2 strands, with the scoubidou plastic you just
hold them besides each other. Make sure there are at least three knots over
the two strands together.
When you make this
knot in the plastic strands you also finish with the last two knots extra
tight. If you do not like the look, or work with different string, keep the
last three knots loose, work the strands in and than tighten those knots.
This way looks better but is harder to do. If neither works, glue might be
the rescue, test for melting string.