\caption{An emergent language that the unilateral metrics cannot measure its non-compositionality. Notice that when $s_1=\mathrm{a}$, the listener can neither determine the shape nor the color without the knowledge about $s_0$.}
\caption{An emergent language that the unilateral metrics cannot measure its non-compositionality. Notice that when $s_1=\mathrm{a}$, the listener can neither determine the shape nor the color without the knowledge about $s_0$.}