$s_2$

$t_2$

$\left(s_1\mathrm{,}{s}_3\right)$

(1, 1)

(4, 2)

$\left(t_1\mathrm{,}{s}_3\right)$

(6, 3)

(7, 7)

$\left(s_1\mathrm{,}{t}_3\right)$

(7, 4)

(2, 1)

$\left(t_1\mathrm{,}{t}_3\right)$

(9, 3)

(7, 1)