1. "So we need to find the best route that avoids all the rocks."
2. "But the impurities in each low-purity magic crystal are different, and we can't feasibly research them one by one, right?"
3. "Oh... Yeah, right."
4. "If we can find a sample medium where magic flows very well, test the best diagram for the mana channels on it, and then carve it onto the crystal,"
5. "We should be able to avoid most of the impurities, right?"