Romeo and Juliet are the only two consumers in an economy with two goods $x$ and $y$, and Romeo's endowment is $\omega^R=(0,1)$ while Juliet's is $\omega^I=(1,0)$. They each choose their consumption levels of the goods independently. But because they are madly in love, they get satisfaction not only from their own consumption of the goods but also from the other's consumption of both goods:
$$
\begin{gathered}
u^R\left(x^R, y^R, x^I, y^I\right)=x^R y^R+x^I+y^J, \\
u^J\left(x^R, y^R, x^J, y^J\right)=x^J y^I+x^R+y^R .
\end{gathered}
$$
(a) Find the contract curve for this two-person Edgeworth box.
(b) Find a Walras equilibrium. Is it Pareto efficient? Explain why or why not.