Stretched Chord - Step 1 - How to set up a Chord Diagram matrix to show Flows

Step 1 (out of 6) from my blog on How to create a Flow diagram with a circular Twist in which the data has been set up in such a way that all chords flow only between arcs on the left and right half

• The next step
• The final step

An example based on actual data can be found here

forked from nbremer's block: Stretched Chord - Step 1 - How to set up a Chord Diagram matrix to show Flows