Flowchart: Parallel Edges with Back Edges (TD)
Four edges down and two back between the same two nodes in a top-down graph (#1826). In the ASCII panel the faces they share grow so each edge keeps its own arrowhead.
flowchart-parallel-edges-with-back-edges-td.mmd
flowchart TD
A -->|f1| B
A -->|f2| B
A -->|f3| B
A -->|f4| B
B -->|b1| A
B -->|b2| A