digraph g { # size="800,800"; compound=true; concatenate=true; subgraph cluster_wallet { style=filled; color=lightgrey; webex [label="wallet-webex"]; android [label="wallet-android"]; legacy [label="wallet-legacy"]; label="Wallets"; } android -> merchant_frontend [label="buy", ltail=cluster_wallet]; merchant_frontend -> merchant_backend [dir="both"]; merchant_frontend [label="merchant (frontend)"]; merchant_backend [label="merchant (backend)"]; android -> exchange [label="withdraw", ltail=cluster_wallet, dir="both"]; merchant_backend -> exchange [label="deposit"]; android -> bank [label="select exchange", ltail=cluster_wallet]; bank -> exchange [label="wire transfer", dir="both"]; }