"Allow me to prepare the barrier, and then we can begin our game", he said. He picked up the ball in one hand and moved his other hand around it, putting some sort of enchantment on it; then he put it down again. He walked around the table, stopping at about one meter and a half away from its edge; then his fingers started spinning once more. A faintly glowing blue line appeared underneath his feet and started to move around the table, like ink trailing behind an invisible brush. Adrien watched the line crawl by his feet on the stone floor until it closed upon itself, forming a border around the ping-pong table.