"Grayscale contrast" in the attached pictures is not allowed.
Attachments should be drawn or printed with drawing tools and black ink. The lines should be even and clear and must not be altered.
"Grayscale contrast" means that the lines in the drawing are dark or light, uneven, or even have areas with gray filling or grayscale changes, which is not allowed.
It can also be understood that the attached drawing must be a uniform and clear wireframe diagram without any shadows or gray surfaces.