Valerion smiled. "You must have imagined the fireball more vividly; that means that the concept of the fireball is easier for you to bring into reality than the bat or the wall".

"I see", Adrien nodded. "So, what happens now?".

"Could I ask you to think of the fireball once more?", Valerion gently asked.

"Oh -- of course". Adrien placed himself in position. A paper ball flew into Valerion's hand; he made it bounce once in his palm, then threw it. Adrien drew an arc, thinking of the fireball again; this time he could distinctly see it fly from somewhere within his circle towards the boundary, where it met the paper ball and set it on fire. He reflexively stepped back; the ball of paper and flames fell on the floor, where it kept on burning for a few seconds before leaving only ashes behind.

"Well done", Valerion commented, clapping his hands. "Well done. However, you should not step back; try to stand still when the paper starts to burn".