edge { arrowstyle: filled; }
graph {
  colorscheme: x11;
  flow: south;
  title: SPLIT;
}

[ nil|  |  | 0 ] { basename: 0; }
[ nil|  |  | 1 ] { basename: 1; }
[ nil|  |  | 2 ] { basename: 2; }
[ nil|  |  | 3 ] { basename: 3; }

[ 0.0 ] --> [ 1.3 ]
[ 0.3 ] --> [ 1.0 ]
[ 2.0 ] --> [ 3.3 ]
[ 2.3 ] --> [ 3.0 ]