Left hand rotated by supination extending left index finger to pass purple strand through loop. Regrasp purple strand with right hand. The loop is slid onto the thumb of the left hand by pronating the pinched thumb and index finger of left hand beneath the loop. Purpel strand drawn left with right hand and again grasped between thumb and index finger of left hand. Left hand rotated by supination extending left index finger to again pass purple strand through forming a double loop.
Horizontal tension is applied with the left hand toward and right hand away from the operator.
This double loop must be placed in precise position for the final knot. With thumb swung under white strand, purple strand is grasped between thumb and index finger of left hand and held over white strand with right hand. Purple strand released. Left hand supinates to regrasp purple strand with index finger beneath the loop of the white strand. Purple strand rotated beneath the white strand by supinating pinched thumb and index finger of left hand to draw purple strand through the loop.