$s_3$

$t_3$

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

(2, 0)

(6, 5)

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

(7, 2)

(10, 2)

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

(3, 3)

(1, 2)

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

(12, 2)

(5, 3)