Blood · Breath · Nerve · Pulse · Vein

Blood is a carrying fluid. A Vein is a channel, in a body or in a leaf or in ore, that the fluid did not invent. A Nerve is a different channel: charge instead of volume. A Pulse is the surge repeating in whichever medium will take it. Breath is the other circulation, air crossing a living edge and leaving changed.

Vessel is five, not six: the set is already a complete circuit. Water and Motion take the split. Electricity is the nerve’s medium. Wave is the surge. Human is the body that happens to hold all three at once. The map keeps the plumbing, not an organ named Heart.