graph {
  fill: peru;
  border: 1px dashed blue;
  }
group { fill: peru; }

  [ Bonn ] - > [ Berlin ] { shape: circle; fill: darkslategrey; background: brown; color: white; }
  [ Bonn ] ==> [ Frankfurt ] { fill: #deadff; }
  [ Berlin ] ..> [ Cottbus ] { shape: ellipse; }
  [ Berlin ] -> { color: green; } [ Bonn ] { fill: #ffdead; }
  [ Cottbus ] = > [ Frankfurt ]
  [ Berlin ] -> { arrow-style: closed; } [ Ulm ]
  [ Ulm ] { shape: house; } .-> { color: #a02020; } [ Koblenz]
  [ Ulm ] ..-> [ Konstanz ] { shape: diamond; fill: peru; border: none; background: yellow; }
  
  [ Konstanz ] --> { arrow-style: filled; fill: red; } [ Mainz ] { shape: triangle; }
 
  [ Koblenz ] { shape: invtriangle; } 

node.point { shape: point; flow: south; }
node.doublepoint { border-style: double; shape: point; flow: east; }
node.double { border: double white; fill: palevioletred; }
node.doubledash { border: double-dash yellow; fill: crimson; }

( Stars   
  [ A ] { point-style: star; color: red; } ->		# background ignored
  [ B ] { point-style: circle; fill: dodgerblue; } ->
  [ C ] { point-style: circle; fill: white; } ->
  [ D ] { point-style: square; fill: firebrick; flow: west; } ->
  [ E ] { point-style: diamond; fill: lime; } ->
  [ F ] { shape: invisible; background: coral; } ->
  [ G ] { point-style: dot; color: slategrey; } ->	# background ignored
  [ H ] { point-style: circle; fill: black; } ->
  [ I ] { point-style: cross; color: darkblue; }	# fill ignored
) { nodeclass: point; }

( 
 [ Rect ] 
  <--> [ Circle ] { shape: circle; }
  <--> [ Ellipse ] { shape: ellipse; }
  <.-> [ House ] { shape: house; }
  <.> [ InvHouse ] { shape: invhouse; }
  <= > [ Triangle ] { shape: triangle; }
  <- > [ InvTriangle ] { shape: invtriangle; flow: south; }
  <..-> [ Octagon ] { shape: octagon; flow: south; }
  <..-> [ Diamond ] { shape: diamond; flow: east; }
  [ Triangle ] <==> [ Hexagon ] { shape: hexagon; }
  <==> [ Pentagon ] { shape: pentagon; }
  <==> [ Septagon ] { shape: septagon; }
  [ Pentagon ] <==> [ Parallelogram ] { shape: parallelogram; }
  [ Hexagon ] -- [ Trapezium ] { shape: trapezium; }
  [ Hexagon ] .-.- [ Invtrapezium ] { shape: invtrapezium; }
) { nodeclass: double; }

[ A ] -> [ AB ]

( Stars2
  [ AB ] { point-style: circle; fill: dodgerblue; } ->
  [ AC ] { point-style: circle; fill: white; } ->
  [ AD ] { point-style: square; fill: firebrick; flow: west; } ->
  [ AE ] { point-style: diamond; fill: lime; } ->
  [ AF ] { shape: invisible; background: coral; } ->
  [ AG ] { point-style: dot; color: slategrey; } ->	# background ignored
  [ AH ] { point-style: circle; fill: black; } ->
  [ AI ] { point-style: cross; color: darkblue; }	# fill ignored
) { nodeclass: doublepoint; }
 
( Rect2 
 [ DRect ] { origin: Frankfurt; offset: 0,4; } 
  <--> [ DCircle ] { shape: circle; }
  <.-> [ DHouse ] { shape: house; }
  <.> [ DInvHouse ] { shape: invhouse; }
  <= > [ DTriangle ] { shape: triangle; }
  <- > [ DInvTriangle ] { shape: invtriangle; flow: south; }
  <..-> [ DOctagon ] { shape: octagon; flow: south; }
  <..-> [ DDiamond ] { shape: diamond; flow: east; }
  [ DTriangle ] <==> [ DHexagon ] { shape: hexagon; }
  <==> [ DPentagon ] { shape: pentagon; }
  <==> [ DSeptagon ] { shape: septagon; }
  [ DPentagon ] <==> [ DParallelogram ] { shape: parallelogram; }
  [ DDiamond ] -- [ DTrapezium ] { shape: trapezium; }
  [ DHexagon ] .-.- [ DInvtrapezium ] { shape: invtrapezium; }
) { nodeclass: doubledash; }