Polargraph using big steppers

I built a polargraph as a school project and adapted it to do woodburning. Now it's my hobby. I am here because I need to do some modifications. 

I have been doing some large pyrographic projects, and considering how slow it is, necessarily so, there is a big investment in time and wood and it's a real bummer if for some reason it should drop some steps, which it has. That is why I want to use larger motors and controllers. 

The problem is, I am not a programmer, at least not recently, and I am dependent upon the open source sketches and libraries that were provided by Sandy Noble (credits in the sketches). My question is, does the polargraph controller software and libraries require the use of the motor shield module? It would be great if I could just piggyback the controllers right off the motorshield, but Bill's demo using an arduino with large stepper only used one stepper and controller and no motorshield. 

I hope my question makes sense.