1
Make a loop somewhere in the middle of a rope.
2
Make two more loops. Note how the left loop goes under the middle loop and the right one goes over.
3
Gently tease the edges through the loops on either side. Notice that one goes above and one below.
4
Grab the edges of the middle loop, the left from underneath, the right from above.
5
Keep pulling while making sure the loops tighten around the grabbed part.
6
When all is snug, pull on the two ends. As long as there is tension, the knot will stay in place.