It is easy to learn about cutting a piece of paper but very difficult to master it with perfection. One must grasp the knife in an upright fashion and press evenly on the paper with some strength. Flexibility is required but any hesitation or wiggling will lead to imprecision or damage the whole image. Engravers stress the cutting lines in several styles and there are four ideal but basic lines that they endeavor to master. They attempt to carve a circle like the moon,a straight line like a stem of wheat,a square like a brick,and jaggedly like the beard.