$s_3$

$t_3$

$\left(s_1\mathrm{,}{s}_2\right)$

(11, 5)

(7, 3)

$\left(t_1\mathrm{,}{s}_2\right)$

(6, 3)

(9, 7)

$\left(s_1\mathrm{,}{t}_2\right)$

(−1, 4)

(5, 4)

$\left(t_1\mathrm{,}{t}_2\right)$

(4, 4)

(1, 5)