distortion

type: double, default: 0.0, minimum: -100.0

Positive values cause top part to be larger than bottom; negative values do the opposite.

See also skew.

graph {
  LargeBottom [shape=polygon sides=4 distortion=-.5]
  LargeTop    [shape=polygon sides=4 distortion=.5]
}

• Nodes

Search the Graphviz codebase for "distortion"