心无一人空似池城心似池城空无一人
[xīn wú yī rén kōng sì chí chéng xīn sì chí chéng kōng wú yī rén]
Portrays inner loneliness despite physical connections with others. The heart, like an empty city devoid of population (or significant relationships), illustrates profound solitude felt by the soul or mind.