Alpine Butterfly

Make a fixed loop in the middle of a rope without using either end.

Dress the two shoulders evenly and check the central crossings.

Step-by-step

Start in the middle
Keep both ends outside the working area. Form the knot in the middle of the rope.
Lift a bight
Lift the middle into an open bight.
Twist once
Twist the bight to form the first opening.
Twist again
Twist in the same direction to make two stacked openings.
Fold the top loop behind
Carry the upper closed fold behind the lower opening.
Go around the lower loop
Pass outside both sides of the lower opening.
Bring the fold below
Carry the closed fold below the standing line.
Return in front of the opening
Bring the fold toward the front of the lower central opening.
Pass through the middle
Draw the closed fold through the original lower opening from front to back.
Extend the loop
Draw the closed bight upward.
Dress the butterfly
Draw the loop upward and the standing parts outward as the collars gather.
Inspect the route
The same rope forms two opposite standing parts and an upper loop.