The Graphviz code for Example 1

digraph fig1
	{
		a -> d [label="1"];
		b -> d [label="2"];
		c -> d [label="3"];
		e -> a [label="2, 3", fontcolor= red, color=red, decorate];
		e -> b [label="1, 3", fontcolor= red, color=red];
		e -> c [label="1, 2", fontcolor= red, color=red];
	}
	
	
The Graphviz code for Example 2
	
digraph fig2
	{
		a [pos = "1, 1.73!"];
		b [pos = "2, 0!"];
		c [pos = "0,0!"];
		d [pos = "1,.58!"];
		a -> b [label = "1,3", fontcolor= red, color=red];
		a -> d [label = "1", decorate];
		b -> c [label = "1,2", fontcolor= red, color=red];
		b -> d [label = "2"];
		c -> a [label = "2, 3", fontcolor= red, color=red, decorate];
		c -> d [label = "3"];
	}