Agree. Picking complementary colours 180 degrees separated in HSL space almost always creates an (IMO) clashing combination.

102 degrees would have been more sensible, while providing sufficient contrast.

Using a different, more perceptually-based colour space would be even better.

Fortunately the code is available for you to play with:

https://github.com/mgiraldo/tenprintcover-p5

This other project has some interesting geometric explorations:

http://variable.io/generative-covers/