Final answer:
Repeating lines in a hairstyle can be curved or straight and have different effects on the overall look.
Step-by-step explanation:
The design lines in a hairstyle that can be curved or straight are known as repeating lines. These lines can add different effects and movement to the hairstyle. For example, curved repeating lines in a hairstyle can create a sense of flow and softness, while straight repeating lines can create a more structured and angular look.