Step 1: Divide the four strands into left and right groups (Figure 1).
Step 2: Bring the outside right strand under the two inside strands and then back over the right inside strand (Figure 2). The outside right strand becomes the inside right strand.
Step 3: Bring the outside left strand under the two inside strands and then back over the left inside strand (Figure 3). The outside left strand becomes the inside left strand.
Repeat Steps 2 (Figure 4) and 3 (Figure 5) to desired length.