Explanation: When Julius Caesar was sieging the Gallic fortified town of Alesia, he built two walls - one to keep the Gauls in Alesia, in Alesia; and one to keep Gallic reinforcements out of his camp, leaving the Romans nestled between the two armies. A siege within a siege!

Yo dawg. I heard you liked walls. So we put a wall behind yo wall so you can siege while being sieged.

Reminds me of the "Just one more road" meme. Come on guys we just to need to build more wall then we will be secure!

Explanation: When Julius Caesar was sieging the Gallic fortified town of Alesia, he built two walls - one to keep the Gauls in Alesia, in Alesia; and one to keep Gallic reinforcements out of his camp, leaving the Romans nestled between the two armies. A siege within a siege!