Incoming ports drop to where they are first needed. Not to where most of their current ends up — that would push a port below its own early customers and make those ribbons climb. Outgoing ports do the mirror: they align on the rail carrying their highest current, level with whatever feeds it.
Logic blocks. Open any consumer or port and pick a block under Logic block, or make a new one. Members are kept together and drawn inside a labelled box, so the plot can be aligned to your block diagram. A block that loses its last member is removed rather than left as an empty label.
Converter edges carry their voltage. The rail going in on the left, the rail coming out on the right — a converter is the one card whose two sides differ, and that is what you want to read without opening it. Two stages in series share one rail, so it is written once, centred in the gap.
Rows grow to hold their ribbons. A regulator feeding five consumers gets a taller row, so the fan-out lands inside the card the way it would in a real Sankey. Rows that do not need the space keep the normative height, which is what keeps a collapsed card readable at a glance.