a pencil - from the outside of the left half. place it over the top of the left half, then join it to the inside edge of the right half. by inside edge, we mean the middle of the braid. don't tuck the piece underneath, just gather it with the rest.
take a piece of hair from the outside of the right half, lay it over the top of the right half, then gather it on the inside edge of the left half.
repeat steps 3 and 4 until you get to the ends, then secure with a hair tie.
to loosen the braid, gently pull it out slightly with your hands, then 