This document discusses different principles of lines including vertical, horizontal, diagonal, jagged, zigzag, curved and crossed lines. It describes masculine lines as energetic, aspiring and vital while feminine lines are described as yielding, harmonious and relaxed. Warning lines are said to alert danger and draw the eye across a page strongly while impact lines imply speed, hard energy and danger. Feminine lines are described as gentle, soft, relaxed and organic compared to chaotic lines that create panic.