Water jet four-axis drawing needs to determine the direction of the line, that is, clockwise or counterclockwise. There is another biggest difference, that is, you can't cut at the edge of * * *, and everything else is the same as three axes! If you know how to draw three axes, don't worry about four axes, it's easy to get started. If you are afraid of making mistakes in dealing with the direction of lines, you can use the "cliff water knife toolbox" to solve this problem.