Can anyone tell me if this page Graph Object Wishlist - WeBWorK_wiki (maa.org) was implemented or not?
I am particularly interested in the section "part I. Introduction"
It's doubtful that any of that was implemented as described.
WeBWorK 2.16 offers the ability to embed TikZ images, which would give you the ability to generate graphs dynamically using an existing package. I've never used it myself, so I don't know if it handles piecewise graphs, but I assume that there is a way to do it.