This is cool. It reminds me of 3D printers, but just in two dimensions and with a paintbrush and paint instead of a hot-end/nozzle/filament. You could look at

This is cool. It reminds me of 3D printers, but just in two dimensions and with a paintbrush and paint instead of a hot-end/nozzle/filament. You could look at the firmware used to control the stepper motors/end stops that much of the reprap community is using at https://github.com/MarlinFirmware/Marlin https://github.com/MarlinFirmware/Marlin. This uses GCODE as well, and deals with acceleration around turns.