# Different edge styles
 [ Bonn ] <-> [ Berlin ] 	# bidirectional
 [ Berlin ] ==> [ Rostock ]	# double
 [ Hamburg ] ..> [ Altona ]	# dotted
 [ Dresden ] - > [ Bautzen ]	# dashed
 [ Schweinfurt ] <=> [ Ulm ]	# bidrectional, double
 [ Magdeburg ] .-> [ Burg ]	# dot-dash
 [ Burg ] -- [ Wolfen ]		# single, bidirectional w/o arrows
 [ Wolfen ] .. [ Coswig ]	# dotted, bidirectional w/o arrows
 [ Magdeburg ] ..> [ Aue ]	# dotted, going downwards

