A chord diagram is a graphical method of displaying the inter-relationships between data in a matrix. The data is arranged radially around a circle with the relationships between the points typically drawn as arcs connecting the data together.
No Tableau examples found at time of writing (August 2016).
A comprehensive post by Noah Salvaterra was hosted on datablick.com, and appears to be the guide to this chart type:
Noah’s work is mind-bogglingly remarkable. There are plenty of examples of wonderfully creative viz’s on his Tableau Public profile, including a couple of chord diagrams:
In August 2016, Chris Love shared this: