Touching NSBezierPaths have ugly space

Hi everyone,

I'm drawing a bunch of NSBezierPaths right next to each other (the yellow to red items, see screenshot). Although their outer coordinates are identical, these tiny light lines show up between them. It's a rendering ting, identical in all zoom levels.
Is anything known how to get rid of these, without shenanigans such as changing coordinates or drawing additional outline strokes? (Both these workaround would be absolute, looking different at different zoom levels)

It's really my first time to touch Cocoa.
Thank you...