Why do most pencils have six flat sides?

                                 

Most pencils have six sides.  If you cut one across and look at the
end, it is shaped like a hexagon.  

There are three reasons for this.

1. It is cheaper to make pencils with six sides because more

pencils can be made from the same amount of wood.  The wood that
could make eight round pencils can be made into nine hexagonal ones.

2. They are less likely to roll off a desk than round ones. 

3. Easier to sharpen than square ones.