The letter, having departed, ruined the designs of hearts; the beauty of the idols' faces was all ruined.

Mir Taqi Mir paints a poignant picture here. The couplet suggests that the mere act of a letter being written and sent has somehow disturbed the delicate, beautiful emotional patterns etched onto hearts. The 'idols'—the superficial joys or beliefs—which were once stable and perfect, have all fallen into disarray because of this emotional upheaval. It speaks to how deep, heartfelt communication can shatter established illusions.