grid4.dot

graph g {
  p0 [algo="p.ml"  ]
  p1 [algo="p.ml"  ]
  p2 [algo="p.ml"  ]
  p3 [algo="p.ml"  ]
  p4 [algo="root.ml"  ]
  p5 [algo="p.ml"  ]
  p6 [algo="p.ml"  ]
  p7 [algo="p.ml"  ]
  p8 [algo="p.ml"  ]
  p9 [algo="p.ml"  ]
  p10 [algo="p.ml"  ]
  p11 [algo="p.ml"  ]
  p12 [algo="p.ml"  ]
  p13 [algo="p.ml"  ]
  p14 [algo="p.ml"  ]
  p15 [algo="p.ml"  ]

  p0 -- p1 -- p2 -- p3 -- p7
  p0 -- p4 -- p5 -- p6
  p11-- p15
  p1 -- p5 -- p9 
  p10 -- p11 -- p7
  p10 -- p14 -- p15
  p10 -- p6
  p10 -- p9
  p12 -- p13 -- p14
  p12 -- p8 -- p9
  p13 -- p9
  p2 -- p6 -- p7
  p4 -- p8
}