graph Perl
{
graph [ rankdir="TB" ]
node [ shape="oval" ]
edge [ color="grey" ]
"13" [ color="invis" label="" shape="point" width="0" ]
"27" [ color="invis" label="" shape="point" width="0" ]
"20" [ color="invis" label="" shape="point" width="0" ]
"13" -- "27" [ color="cornflowerblue" label="Top row\nBottom row" ]
"27" -- "20" [ color="red" label="Edges use cornflowerblue and red" ]
}