Given the following diagram, where A is a parallellogram. Written $s=-u+2v$ and $v=\frac13s+\frac16t.$ Now I want to find $a,b,c$ and $d$ such that $$A=\{P \mid \vec{OP}=xu+yv \text{ where } x\in[a,b] \text{ and } y\in[c,d]\}. $$
I have tried different things but nothing works. I have used the linear combination and I get $$-\frac13xs+\frac13xt+\frac13ys+\frac16yt$$ which does not help.