No supports required. Print with white filament and then paint or colour the outside layer with a black marker. I used PLA but I suggest using PETG to get better layer adhesion so the ink does not flow between the print layers.
I have provided slices at 100, 75 and 50% scale.

For a brief overview of the print prep and application, check out this video:
https://youtube.com/shorts/FYvl55NpnjU