hscale=0.5;
a, c, b[pos=-0.7], d[pos=-0.7], e, f[pos=-0.7];

{
    defstyle arrow [color=red];
    a->b; a->b; a->b; a->b;
    a->b; a->b; a->b; a->b;
} {
    c->e [color=blue];
    [layout=one_by_one_merge] {
        defstyle arrow [color=green+20];
        c->e; c->e; c->e;
    } {
        defstyle arrow [color=green-20];
        d->f; d->f; d->f;
    };
    c->e[color=blue];
};
vertical brace: \-Layout is\n\bone_by_one_merge;
---;
{
    defstyle arrow [color=red];
    a->b; a->b; a->b; a->b;
    a->b; a->b; a->b; a->b;
} {
    c->e [color=blue];
    [layout=one_by_one] {
        defstyle arrow [color=green+20];
        c->e; c->e; c->e;
    } {
        defstyle arrow [color=green-20];
        d->f; d->f; d->f;
    };
    c->e[color=blue];
};
vertical brace: \-Layout is\n\bone_by_one;
