Stretched Chord - Step 2 - How to create an empty section in between the two halves

Step 2 (out of 6) from my blog on How to create a Flow diagram with a circular Twist in which a dummy arc (in light grey) has been added to visually separate the source of the flows and the target of the flows.

• The previous step
• The next step
• The final step

An example based on actual data can be found here