@nelson Yep, just crosshatches manually generated by the Eggbot Inkscape Hatch Fill extension. (spacing set to 0.5px)

@nelson For these colors I mixed them by setting different angle hatches for each color/proportion.

@nelson e.g. for blue (C 33% and M 67%) it was cyan with a horizontal hatch and magenta with 45° hatch and a 135° hatch