How did Donatello create the relief panel St. George Killing the Dragon?

Donatello created the marble relief panel St. George Killing the Dragon (1416–1417) by inventing a bold, innovative technique known as schiacciato (meaning "flattened out").1

Rather than modeling shapes in the traditional manner, Donatello used his chisel to "paint" the scene. This method involves extremely shallow carving throughout the panel, where the design is partly defined by finely engraved lines and partly by subtle variations in relief. By manipulating these planes with great delicacy, he created a striking illusion of atmospheric space and depth while maintaining the integrity of the marble surface. This technique relies heavily on how the material—typically white marble—responds to light, allowing the most delicate textures and changes in relief to become visible.123