digraph G {
  "Person" [label="class\nPerson",shape=box];
  "Student" [label="class\nStudent",shape=box];
  "ferris" [shape=doublecircle,label="object\nferris"];
  "LaidBack" [shape=circle,label="trait\nLaidBack"];
  "Cool" [shape=circle,label="trait\nCool"];
  "Person" -> "Student" [label="(extends)"];
  "Student" -> "ferris" [label="(extends)"];
  "LaidBack" -> "ferris" [style=dotted,label="(mixes in)"];
  "Cool" -> "ferris" [style=dotted,label="(mixes in)"];
}
