Blackstar
Among the many blueprints Leonel's father had left behind, there were even a few buildings among them. To this point, Leonel had mostly ignored them, focusing on the designs that could hone his skill in armor crafting.
That said, this didn't mean that he had never looked over them. In fact, he had memorized them all already. They were able to give Leonel a basic understanding of construction and the physics that went behind it.
Most of it was quite simple in Leonel's estimation, just understanding forces like tension, compression, shearing and the like. He had already learned about all these things in high school.
Plus, even if he hadn't, he could just test his design plans within his Dream World. If he did things like that, he would hardly need to think at all.