There is a graph "chord graph" to show the movement between 2 class or clusters. It's this graph : https://github.com/microsoft/powerbi-visuals-chord .
I Think that is very interesting to add an additional elements of information like this :
Red arrow : show the sum of movement
Yellow : only the part of out flow
Black : only the part of in flow
It's to compare the in VS out VS sum and the importance of the "flow". If it's a " little " or "big" flow , in case of migration for example.
With the current "chord graph" it's impossible to divide the "package" of in and of out. There is an only group.
Thanks for your help.