"Now, son of man, take a brick and place it before you. Draw a picture of the city Jerusalem on it.
Then make a model of a military siege against the brick: Build siege walls, construct a ramp, set up army camps, lay in battering rams around it.
Then get an iron skillet and place it upright between you and the city - an iron wall. Face the model: The city shall be under siege and you shall be the besieger. This is a sign to the family of Israel.