Which city did God tell Ezekiel to draw on a brick and then lay siege to?

Answer: Jerusalem

Ezekiel drew Jerusalem on a brick (KJV: tile) and acted out a siege with ramps, camps and battering rams as a sign to Israel.

““Now you, son of man, take a brick, place it before you, and draw on it the city of Jerusalem.”— Ezekiel 4:1 (BSB)