Farmer's Loop
The Ashley Book of Knots relates, "The Farmer's Loop is shown by Professor Howard W. Riley in ... a pamphlet of 1912, which is devoted to knots employed on the farm.  ...[T]he method of tying it is both ingenious and distinctive, and, once mastered, it is not apt to be forgotten."

The Farmer's Loop seems to resist jamming, but is probably best avoided in stiff or slippery rope where it can shift into different configurations and contract.  The shape it assumes when tied is highly variable, making it somewhat difficult to ascertain its range of properties.

Play leapfrog from the center position three times as shown by the arrows.  On the fourth move, pull the center cord to form the loop.  As you may have guessed, the size of this loop
on the bight is determined by the size of the initial coils.

Related Pages:
Butterfly Loop, Span Loop, Artillery Loop, Pile Hitch