# Three non-overlapping groups

group.dmz { background: #ffa070; }
group.outer { background: #f07070; }

( Internal Network
  [ Workstation ]
) { background: #70b070; }

[ Workstation ] --> [ Inner Firewall ]

( DMZ
[ Inner Firewall ] -> [ Proxy ]
--> [ Outer Firewall ]
) { class: dmz; }

( Outer
  [ Internet ]
) { class: outer }

[ Outer Firewall ] --> [ Internet ]

[ Proxy ] --> [ Database ]