Here is one embedded topology and file that represetns it. Red dot is the driver, and black dots are sinks. Circled sink represents the critical sink for this topology in respect to technology parameters used to generate it.

TOPOLOGY sample6 1
  DRIVER D1 4725 5900 0
  SINKS
    T3 7750 8275 0
    T4 8125 7350 0
    T6 6200 3550 0
    T5 3825 3675 0
    T2 2100 7725 0
  END
  STEINERS
    S5 6200 5900 0
    S3 6200 7350 0
    S2 7750 7350 0
    S1 7750 7725 0
    S4 6200 3675 0
    S8 3825 5900 0
    S7 2100 5900 0
    S6 2100 7350 0
  END
  EDGES
    D1 S5 1.0
    D1 S8 1.0
    S5 S3 1.0
    S5 S4 1.0
    S3 S2 1.0
    S2 S1 1.0
    S2 T4 1.0
    S1 T3 1.0
    S4 T6 1.0
    S8 T5 1.0
    S8 S7 1.0
    S7 S6 1.0
    S6 T2 1.0
  END
END