digraph {
  rankdir=LR
  node[shape=record]

  obj1[label="<cnt>refcount: 1
             |size: 8
             |...
  ",xlabel="object"]

  free1[label="<next>next-free
              |size: 12
              |...
  ",xlabel="free block"]

  free2[label="<next>next-free
              |size: 200
              |...
  ",xlabel="free block"]

  obj1:cnt->free1:next[style=invis]
  free1:next->free2:next->{null1[shape=point]}

}