Glen Pedro of Woodbridge, NJ, USA taught me this knot. It is a great way to belay a flying line to a carabiner. At the end of the flight, this knot is easy to open up and slide off the 'biner, and then it just falls apart.
Start with a Lark's Head:
Put a 180 degree twist in one leg:
Then twist it another 180 degrees:
Make the other one look the same. Twist the opposite way, 360 degrees.
Open the carabiner, and put it thru the loops.
Tighten it down.
We have tied off Suttons and Mantas and Octopii and lots of others with this knot.