digraph G {
  subgraph cluster_2 {
    ubank;
    nexus;
    rank="same"; ebank; mbank;
    label="Fiat currency";
  };
  subgraph cluster_1 {
    user;
    exchange;
    shop;
    rbank;
    label="Regional currency";
  };
  subgraph cluster_2b {
  }
  user[label="Customer (Wallet)"];
  shop[label="Merchant (Backend)"];
  exchange[label="Exchange"];
  ubank[label="Customer Fiat Bank"];
  ebank[label="Exchange Fiat Bank"];
  mbank[label="Merchant Fiat Bank"];
  rbank[label="Regional Currency Bank"];
  user->ubank [label="1. Initiate withdraw"];
  ubank->ebank [label="2. Wire transfer"];
  ebank->nexus [label="3. EBICS (CAMT)"];
  nexus->rbank [label="4. Conversion (Cash-in)"];
  rbank->exchange [label="5. Wirewatch"];
  exchange->user [label="6. Withdraw E-Cash"];
  user->shop [label="7. Spend E-Cash"];
  shop->exchange [label="8. Deposit E-Cash"];
  exchange->rbank [label="9. Credit Shop"];
  rbank->nexus [xlabel="10. Conversion (Cash-out)"];
  nexus->ebank [label="11. EBICS (PAIN)"];
  ebank->mbank [label="12. Wire-transfer"];
}