// prolog example
digraph {
	context -> "context; prolog example" [label="" arrowhead=normal]
	context -> "context; global context" [label=previous arrowhead=normal]
	sally -> trude [label=mother arrowhead=normal]
	sally -> tom [label=father arrowhead=normal]
	sally -> 16 [label=age arrowhead=normal]
	erica -> trude [label=mother arrowhead=normal]
	erica -> tom [label=father arrowhead=normal]
	erica -> 12 [label=age arrowhead=normal]
	trude -> sara [label=mother arrowhead=normal]
	trude -> sam [label=father arrowhead=normal]
	trude -> tom [label=husband arrowhead=normal]
	trude -> sally [label=daughter arrowhead=normal]
	trude -> erica [label=daughter arrowhead=normal]
	trude -> 38 [label=age arrowhead=normal]
	peter -> ruth [label=mother arrowhead=normal]
	peter -> mike [label=father arrowhead=normal]
	peter -> 26 [label=age arrowhead=normal]
	tom -> ruth [label=mother arrowhead=normal]
	tom -> mike [label=father arrowhead=normal]
	tom -> trude [label=wife arrowhead=normal]
	tom -> sally [label=daughter arrowhead=normal]
	tom -> erica [label=daughter arrowhead=normal]
	tom -> 40 [label=age arrowhead=normal]
	sara -> sam [label=husband arrowhead=normal]
	sara -> trude [label=daughter arrowhead=normal]
	sara -> 56 [label=age arrowhead=normal]
	sam -> sara [label=wife arrowhead=normal]
	sam -> trude [label=daughter arrowhead=normal]
	sam -> 56 [label=age arrowhead=normal]
	ruth -> gina [label=mother arrowhead=normal]
	ruth -> mike [label=husband arrowhead=normal]
	ruth -> tom [label=son arrowhead=normal]
	ruth -> peter [label=son arrowhead=normal]
	ruth -> 57 [label=age arrowhead=normal]
	mike -> mary [label=mother arrowhead=normal]
	mike -> mark [label=father arrowhead=normal]
	mike -> ruth [label=wife arrowhead=normal]
	mike -> tom [label=son arrowhead=normal]
	mike -> peter [label=son arrowhead=normal]
	mike -> 60 [label=age arrowhead=normal]
	gina -> ruth [label=daughter arrowhead=normal]
	gina -> 76 [label=age arrowhead=normal]
	mary -> mark [label=husband arrowhead=normal]
	mary -> mike [label=son arrowhead=normal]
	mary -> 76 [label=age arrowhead=normal]
	mark -> mary [label=wife arrowhead=normal]
	mark -> mike [label=son arrowhead=normal]
	mark -> 78 [label=age arrowhead=normal]
}