A stunning, close-up conceptual piece of a mechanical heart made of brass, copper, and tempered glass, in the ornate and technical style of Fiona Marchbank. The heart is a dense, pulsating cluster of interlocking gears, tiny escapements, and rhythmic pistons, all rendered with impeccable fine-line detail and mechanical logic. The art style captures the different metallic textures—the dull, warm glow of brushed copper versus the sharp, brilliant reflections of polished brass—entirely through the density and direction of the hatching. Tiny drops of lubricating oil are visible on the moving gears, and the glass chambers are filled with glowing, stippled vapors and fine electrical arcs. The background is a dark, textured parchment or aged blueprint, making the golden machine pop with intensity. The composition is centered and perfectly symmetrical, emphasizing the "perfection" of the clockwork engineering. The atmosphere is "elegant, industrial, and mesmerizingly complex."