box A;
boxcol Cont: Container
    [line.corner=round] {
    box B, C;
}
box D;
A->B<<D;
A<=>C<D [arrow.endtype=double_empty];
A<>D [color=red, via=Cont@top]: middle;
10%: head [color=red];
mark 90%: tail [color=red];

