"Hmm…" Melissa thought for a moment. "I understand the concept. I don't think it's hard to actually make them. Should I inscribe some magic circle for the propelling as well?
"If I do this, it will last longer than the mechanical one. In addition, it will be more accurate and more efficient."
Nathan shook his head. "Unfortunately, the current system doesn't allow for the magic one." Nathan couldn't see how he could modify the contract to suit this need. After all, there was one big problem.
It seemed Melissa had seen through the problem. She started drawing something. "In that case, I will go with the mechanical one."
"Is it hard to make? How long do you need to finish it?" Vivian asked.
"It's not that hard. To be honest, the launching device is similar to the ballista, and I only need to rearrange it with something I have made before, which is not a hard thing to do."