Weyl group of a rank-two root system
= Weyl group of a rank-two root system
The two simple reflections generate a <dihedral group>. For $A_1\times A_1$, $A_2$, $B_2$, and $G_2$, the rotation has order $2,3,4,6$, so the Weyl groups have orders $4,6,8,12$ respectively.