From outside the syllabus

Since Lex was focusing on the instructions he was receiving in his mind, he did not notice the faint emotion which emerged in Cassandra's eyes. But since she did not make any additional changes to his training program, it did not seem to matter.

He was repeating the moves as close to perfect as he could, and he felt himself improving with each swing. The reason why Lex always felt like his swordsmanship was lacking was because although the sword swing seemed fine, he was able to detect flaws in his body, or weight distribution, or something else. Sometimes, he did not even know what was wrong except that his instincts told him something was missing.

Following the instruction in his mind made a monumental difference, though. Even the smallest change, such as the angle at which he turned his ankle while standing in a certain posture, made all the difference. It was the difference between a straight line drawn using a ruler and a straight line drawn by an artist.