Use the Wii uDraw GameTablet as a digitizer/graphics tablet on your macOS device!
Emulates the basics of the WACOM IV serial protocol on an Arduino.
I used a cheap adapter meant for Wii Nunchuks to connect my board to GND, 5V, SDA, and SCL of the tablet.
Requires TabletMagic
Arduino sketch was modified from mwvent/wii_udraw2arduino2linux
Last, note that although this sketch was written for use on a Teensy++ 2.0, it should work on all Arduino boards that support serial over USB and I2C.