Ballista for Duplicator 4S Build Plate

Build a Ballista for my daughter 3rd grade class on Medieval Times.
I used 10% infill PLA with 3 shells at 200 C extruder temp and 50 C Bed Temp. It has been configured for the Duplicator 4S Build plate.

Note: If using the stl files 2 sets of winders are required, the thing file has all required parts.