I'm asking myself that question a lot today!
I've never really "carved" green florist's styrofoam before...
but now I know why it is suggested that you wear a mask
and have a vacuum cleaner close-by... Ha!
After transferring my BJD pattern to the foam blocks,
I began cutting away to shape the body core
using a small serrated knife... what a mess!
I am using styrofoam balls for the head core
as well as the shoulder and hip core joints.
There will also be joints at the forearms, hands,
knees and feet... theoretically!
Next step... begin to apply paper clay
over the core body parts.