What are these pattern drafting tools used for?

In article , Just Allan of Internet Customer uttered

Use a French curve or a flexible curve - try Morplan, or pos somewhere like Staples

I make patterns only for myself, and continue to use a pattern as long as it fits, so I wouldn't get much benefit from a curved ruler. I do most of my work with rulers, yardsticks, a very large 45-degree triangle, and assorted things left over from my career as a math teacher. When none of the curvy things in my bag of drafting tools will do, I raid the kitchen for plates, jar lids, etc.

I draw hip curves and armhole curves freehand -- one can draw a smooth curve through several points, or connecting two straight lines, if one stands inside it, and lets the pencil rotate about one's wrist, elbow, or shoulder.

If a curve isn't too sharp, and if you have several points along it marked, it's easy to draw it by shifting a ruler.

Joy Beeson